Newbie self-install - please help.

[lazytiger]

Since I'm on a practically non-existent budget for my stereo, I've decided to just put my old CD player (mid-cheap-level Alpine) and amp/sub (Alpine V-power, 12" Type-E) into my Vibe. My visions of putting the '05 OEM sub or a Basslink in there have been crushed, at least for now. To further save $$, I'd like to install this stuff myself. Besides, as long as I don't ruin anything in the process, I figure it will be fun. I'm confident I can do it with a little help from the experts in this forum. I have the M&T package, which seems to be nothin' but trouble with aftermarket equipment. After reading through quite a few threads here, it seems as though the only real solution for putting in an aftermarket receiver is to completely bypass the M&T amp. That's fine by me; I doubt that amp is any better than my Alpine receiver itself (right?). Ragingfish apparently has some schematics for how to bypass the amp without too much hassle. Could I please get a copy of those? However, I don't suppose we're lucky enough for some ready-made harnesses to exist for that, are we? Will I have to ruin the stock harness(es) connecting to the amp? Also, I'm wondering how the tweeters work into the equation - don't tweeters normally need a crossover if coming from a full-range source? How is this handled by the M&T package normally and how will it be handled after I bypass the amp? I'm not going to replace the stock speakers just yet... like I said, I'm on a very tight budget. But how will that affect the tweeters when I do?If you've seen the other threads I've started, you know I want a sub but don't want it to take up any room. Of course, that violates the laws of physics. I've resigned myself to using my old honkin' 12" sub, which sounds great but takes up a lot of room, and just removing it whenever I need to (maybe a few times a month). The amp is attached to the box already, so it's just a matter of hooking and unhooking the wires. But is it safe to leave those wires unattached? Or am I going to have to disconnect it from the battery ever time, too? That would be a hassle. I also want to make sure I have everything I need before I start. I'm looking to get the Metra install kit and wire harness for the Vibe (and I still have the original Alpine harness). Do I need the GM antenna adapter? I've seen threads just about how to get the antenna installed properly! Is it worth the extra $$ to get the stuff from Crutchfield, or should I just get it from wherever it's cheapest? (suggestions?) I'll also get a crimper tool and a bunch of caps. Please let me know if I'm missing anything! Thanks.

[Mr. Poopypants]

If you have Low Level Outputs (LLO, for all intents and purposes they are RCA jacks) on your HU, just run the RCA cables under the passenger side dash and down through the molding, it's very easy to do that. BUT if you want to keep disconnecting the amp and sub, you may want to consider a different mounting point for the amp. If it is small enough, you may want to try mounting it under the rear seats, Mine is mounted under the rear passenger side seat, all you have to do is remove the bolts in front of the seat to get the seat to lift. One word of caution though, I cannot put that seat all the way down because the amp is mounted under there. But anyway, if you don't have LLO, you will have to splice into the wires coming from the head unit or from the wires going into the M&T amp. Get some plain old t splicers to run those wires off the amp. if you have any questions about my rambling, let me know.

[Jahntassa]

Okay...going step by step.The M&T amp IS slightly better than the one built into your headunit. It's 200w at 2 Ohm, yes, so at 4 Ohm, the one in the alpine is technically more powerful..but it'll give a cleaner sound because it's removed from the headunit. Less interference to deal with, better heat dissapation. BUT, with aftermarket speakers, the power stinks.No ready made harnesses, but you don't have to "tear up" the existing ones. Getting useful with a soldiering iron or T-Taps will do just fine. IM ragingfish, he should be able to send you stuff.The tweeters on the M&T are seperately wired, but techincally, you should have no problem wiring them in parallel with the front speakers. You can either get a crossover, or stop by a stereo shop and get "bass blockers", that wire in with the + lead of the tweeters. Should cost you about $10-$20 for the pair. Circuit City has them.I have my amp on my box...and it isn't my preferred method.. It's not "dangerous" to leave the wires hanging, as long as you tape off the ends with ELECTRICAL tape, not duck, not scotch.. ELECTRICAL. Also, removing the under-hood fuse is a good idea. If you can find a place to mount your sub amp, (when I can afford it, an MTX 420 would fit nicely on the side of the hatch area), that'd be best, because then you'd just be disconnecting the speaker wires heading to the sub.You do need the GM Antenna adapter. I don't know where's cheaper for you, but you can get it also from Circuit City (i'm an installer at one, which is why I keep bringing it up.) You need the:Metra 40GM10Metra 80-2003 (or 70-2003)And I forget the dashkit number..That kinda answer your questions? I'm sure Mr. Poopypants might've covered whatever I missed...or..just ask again!

[Jahntassa]

Quote, originally posted by Mr. Poopypants »If you have Low Level Outputs (LLO, for all intents and purposes they are RCA jacks) on your HU, just run the RCA cables under the passenger side dash and down through the molding, it's very easy to do that. He should..I think most, if not all Alpine headunits in the last few years have Sub pre-outs. Thanks for the info about the amp under the seat, though! I was kinda curious if that'd be a clearance problem or not..

[Mr. Poopypants]

Between the two of us, we wrote one hell of a good set of instructions!! LOLThanks for filling in the blanks.

[lazytiger]

Thanks for the info, guys. Putting the amp somewhere else and leaving it is a good idea. It's not a particularly big amp; it's about 10x9x2. But how much ventilation room should it have?I'm looking at the receiver manual, trying to figure out what all the connections on the harness are. I don't see anything about a LLO. And there's only one set of RCA outs, which I'll need for the sub amp unless I pick up some RCA splitters (or is that a no-no?). But in other threads, it sounded like running RCAs to the M&T amp wasn't such a hot idea anyway (introduced all the popping noises) because they have to be spliced. I take it the M&T amp has no RCA inputs?Also, Jahntassa, at Circuit City do they have ready-made harnesses to connect from aftermarket receivers to a bunch of different OEM harnesses? Because I've had more than one stereo installed there, and they never use the harness that comes with the unit. They just seem to have stuff ready to go already. Do they sell those?So I'm still not sure whether it's better to bypass the M&T amp or not. I certainly don't need to double up on the wattage - I've never had a problem with not enough volume. I'm much more concerned with quality of sound. Whichever way achieves that, that's what I want.

[Mr. Poopypants]

You should have more than enough ventilation under the seat. The M&T has no RCA's so your best bet is to forget about it. My next project is to eliminate the amp going to the 6 1/2s all together because it's too much power with the aftermarket HU and the amp.

[ragingfish]

I have NEVER bypassed the M&T amp. Talked about it, but never done it.I haven't a clue what schematics you're talking about.

[lazytiger]

Sorry, ragingfish... I thought that you did. See this thread:http://forums.genvibe.com/zerothread?id=10399Quote, originally posted by Jahntassa »I would agree, however, that you should either bypass the M&T amp, or add an aftermarket 4 channel amplifier. Bypassing the M&T amp is fairly easy, and if you ask Mike (ragingfish) nicely, he can give you the wiring diagrams for the M&T amp to bypass it at the connector to the amplifier, which lets you avoid running all new wires.I might have misunderstood - do you have a schematic for the amp, but nothing specifically about how to bypass it?Mr. Poopypants - Is under the seat the best place? Or how about in the spare tire well (if it fits)? Under the seat definitely isn't the best place if the seatback can't lay down flat. My drums take up every inch of space back there! And I can't imagine the seat's too comfortable to sit on in that case, either.I'm still wanting more details about the tweeters. You say they are wired separately. Does that mean the M&T amp actually has 6 outputs? I assume there's still only 4 channels, though (2 outputs each for the front channels). Is there a built-in crossover (or bass blocker) in the amp for the tweeter outputs?Of course, I'm asking a lot of questions and not digging around in the car very much to try to answer my own questions. Hopefully I can play around a little with it today.

[joatmon]

the wiring diagram for the M&T setup is at http://forums.genvibe.com/zero...o.giflooks like there are six outputs from the amp, so if you replace or bypass the amp, you may need to put in a crossover for the tweeters

[lazytiger]

Thanks for the schematic, joatmon.I'm starting to wonder if I should just let the HU be for now. It seems like the level of complexity caused by the M&T amp isn't the best introduction to car stereo installation. Just installing the subwoofer amp ought to be challenging enough for a first-timer. The only annoying thing about that is if I leave the stock HU, I'll have to wire the amp with speaker line levels instead of RCAs. And I won't have very good adjustment of the bass level.Sigh... decisions, decisions.

[Jahntassa]

Quote, originally posted by lazytiger »I'm looking at the receiver manual, trying to figure out what all the connections on the harness are. I don't see anything about a LLO. And there's only one set of RCA outs, which I'll need for the sub amp unless I pick up some RCA splitters (or is that a no-no?). But in other threads, it sounded like running RCAs to the M&T amp wasn't such a hot idea anyway (introduced all the popping noises) because they have to be spliced. I take it the M&T amp has no RCA inputs?Also, Jahntassa, at Circuit City do they have ready-made harnesses to connect from aftermarket receivers to a bunch of different OEM harnesses? Because I've had more than one stereo installed there, and they never use the harness that comes with the unit. They just seem to have stuff ready to go already. Do they sell those?Second question first: Yes! They do! I didn't mention it in the first post for...i'm not sure why. Bring your reciever with you, because there're two different Alpine harnesses, and getting the wrong one can fry the radio. Usually the part you'll need is the Metra AL-1680, or it could use the Metra AL-2x80 (or something to that effect) If you go back to the roadshop, ask them for the smart harnesses for the 80-2003, and the ALpine in your hand. Oh..and the antenna adapter.Yeah, if you have one set of RCAs, you should use those for the sub. You can run through the M&T amp, and see how it sounds. It's not the best way to do it, but you might not have a problem! And sorry about the confusion, I was under the impression that Mike had helped out someone with bypassing the amp, not done it himself.Alpine harness:Red: Switched power 12vYel: Constant power 12vBlack: GroundBlue: Antenna powerBlue/White: Amp turn-onOrange: IlluminationOrange/Wht: DimmerYel/Brown: Mute (I think that's the right color..you don't need it unless you have a professionally installed handsfree cellular kit)Wht: Left Front +Wht/Blk: Left Front -Grey: Right Front +Grey/Blk: Right Front -Green: Left Rear +Green/Blk: Left Rear -Purple: Right Rear +Purple/Blk: Right Rear -Just as a reference. You can pick up the smart harnesses and plug'ngo. The 80-2003 comes with an extra red power wire that you don't need to use, so don't worry about why it's in the package.

[lazytiger]

Ha ha! My amp fits perfectly into the spare tire well. The four corners are all snug against the side of the well, so the amp just floats there. I think it's pretty secure, though I'm scratching up the plastic a little. Granted, it's upside down, but that hardly matters when it's under the floor anyway. Here's a pic:

Attached files

[ragingfish]

Ok, I see what you're talking about.I was merely helping them wire up the amp so it would turn on...I know nothing about bypassing it.

[Jahntassa]

Quote, originally posted by ragingfish »Ok, I see what you're talking about.I was merely helping them wire up the amp so it would turn on...I know nothing about bypassing it.Oh..I thought you had sent someone a pic of the pinouts for the M&T amp itself.. Maybe it was someone else..?As for the amp, awesome fit! My only concern would be heat. But you can run it like that. If it starts shutting down every once in a while, you might need to cut out a little bit of the spare cover (the black piece the amp is mounted in) and put in a fan or something. A few other members have their amp down there with no problem, though..

[lazytiger]

I see two special harnesses for bypassing the M&T amp... has anyone ever used one of these? Did it work? Was it hard to install?http://www.pie.net/sec11sb11.htmhttp:// ... ...age=1It appears that these harnesses have to be run from the receiver to the amp. Is there a harness out there that allows you to simply unplug the in & out harnesses on the amp and plug them into each other? Know what I mean? Sigh... I bet the 4 channels in and 6 channels out (because of the tweeters) makes this all a lot more complicated.

[Jahntassa]

It shouldn't make it more complicated, but I don't think there's a simple in&out harness like you say. It could probably be constructed from other harnesses, though.. I don't know which harness is which, but if you got a diagram of the harnesses and pinouts, you could probably bypass it all -at- the amp.

[lazytiger]

Quote, originally posted by Jahntassa »...if you got a diagram of the harnesses and pinouts, you could probably bypass it all -at- the amp.That would really be ideal. I have diagrams of the harnesses (though I'm not sure if I have everything I need). But how do I find the harnesses? Are they the same harnesses that are used commonly in GM cars or are they some stupid esoteric things that can never be found?Alright... I'm gonna try to answer some of these questions myself at Circuit City or some other install shop soon. I'll report back to the forum.

[lazytiger]

I stopped by a stereo place I pass by every day and picked up the parts I need for installing the CD player.Metra 70-2003 (wire harness)Metra 40-GM10 (antenna adapter)Metra 99-8205 (install kit)Also, it looks as though all you need to bypass the amp is the Metra 70-2056 harness. I don't think it's meant to just connect the two amp harnesses to each other under the seat, since it comes with way more wire than you need to do that. Regardless, the important part is that it comes with the plastic pinouts that you need to connect them.http://www.autotoys.com/x/cust...age=1However, I think that autotoys.com is grossly overpriced because the guy at the store said he though it would be about $35. Thought being the operative word, though. I'll find out for sure if/when I order it.Now I just need a wire crimper/stripper and some caps to start installing my Alpine! And then find out that I, too, will have the same problems others have had running hot wires from the receiver to the amp, and then end up ordering the other thing to bypass the amp.

[Jahntassa]

Yikes..that is expensive! Probably a stop by Lowes/ Home depot will settle your crimber/stripper problem.. Let us know how it goes!

[lazytiger]

Well, I installed the Alpine tonight... wiring the harnesses together seemed to be no problem. Even though there's a bunch of non-standard colors on the OEM harness, the wires coming out of the Metra harness seemed to make perfect sense - all the various wires (with correct purpose) had corresponding colors on the Alpine harness. So... easy as pie, right? Well not quite. I hooked it all up, put the dash back together, reconnected the battery, and... it powered up, but there's no sound. My only guess is that there is supposed to be a turn-on lead for the M&T amp. But I didn't see anything about it on the OEM schematic. I think all the wires coming out of the OEM harness are already attached to something.Also, my one idiot move of the night - I dropped one of the screws connecting the receiver to the dash down in the dash. How do I take apart the lower dash to try to get it out? Unless it rattles though, I'm not sure I care a whole lot. The receiver seems rock solid with only two screws holding it in.I'm headed back out to the garage now. I'll check back later. Please help. Thanks.

[lazytiger]

SUCCESS! It was just a remote turn-on lead for the M&T amp. Now it works great. All in all, I'm very happy with how smoothly this install went. (Other than my bonehead move of dropping the screw in the dash.) As a first-time installer, I'd have to say that it's not beyond the scope of other novices. All you need to do is get the parts and somewhat fearlessly take apart your dash. Wiring was easy as pie. The Metra harness' wire colors corresponded perfectly with the Alpine's. (However, I can't vouch for other brands.) You don't really even have to pay attention to what the wires are; just connect like-colored wires together. There will be a couple wires that aren't connected to anything (something to do with illumination from the Metra harness; from the Alpine, the power antenna lead is unused); just let those be. Get a 25-count bag of GB twist-on wire connectors (part #25-002; they're the blue ones). They're only a couple bucks and they really do the trick. You don't even need a crimper, though you might need to strip some wires back. I imagine it would be even simpler with the Metra "smart wires," which are available exclusively at Circuit City and are kinda overpriced. You'll pay over $30 for the two parts you need, rather than spending $12 on the traditional Metra harness and using the one that came with your head unit.I know some people were having problems with the radio/antenna... I just plugged in the antenna adapter and the stations around Chicago are coming in as good as ever. Was it luck? Maybe radio signals are exceptionally strong since I'm in Chicago?Anyway, now I'll have to move on to the anticipated problems. The volume level is out of control and there's a very pronounced hiss in the background, just as others have experienced. My next project will be bypassing the M&T amp. Then installing my subwoofer! And someday I'll replace the factory speakers when I have more money.

[AKLGT]

glad you got it all working! sorry i couldn't help, but it was beyond my scope of expertise! LOL

[lazytiger]

Here are some pictures:The Alpine on the kitchen table in the Metra kit.The spliced wire harnessesThe dash, untouched.The dash, touched. Back of the stock stereo.The wire harness in the dash.The finished product.It's tough to get a dark picture in focus! I wish Alpine's lights matched better with the Vibe's red lights, but I don't like any other brands as much as Alpine.

[Jahntassa]

There might've been one or two Alpine HUs that have the red.. I have an Alpine ERA-G230 (I think that's the model)..it's the 14 band EQ. I have it mounted up in my headliner, and it'll switch between the standard Alpine green, and a red that's a fairly close match to the Vibe dash.. Don't know what current HU models do that, though.

[lazytiger]

Alpine seems pretty fixated on their blue and green colors (some of the more expensive units have color matrix displays, but the buttons are still always blue or green). Not that there's anything wrong with that. I think their receivers are way better looking than most any other brand, and I like their functionality the best, too. Unfortunately, it's not the best match for a red-lighted dash. It's like Christmas time all year! But I can deal.My wife has a cheap Sony Xplod CD player in her Beetle (model CDX-L410X, now replaced by the identical-looking CDX-S2000), and its red lights match the Beetle's red dash lights almost perfectly. Its plain silver face (1000 times nicer-looking than any other Xplod model) also blends very well with the Beetle dash, and I imagine it would look really good in the Vibe, too.

[lazytiger]

Installing my Alpine went so smoothly that it's emboldened me to try installing my sub and amp, too. But I also need to take care of the problems caused by the M&T amp. The sound simply isn't very good since I installed the Alpine; there's lots of background hiss, and it's way too loud. The volume increments are absurd. 0 is off, 1 is too loud for background music, 2 is about right for normal listening, it really starts to blast at 3, and I haven't dared to turn it up past 4! I'm sure it would start to blow the factory speakers at 5 (I can't even fathom turning the Alpine up to its limit, which is 30!!). I really don't want to rewire the speakers to bypass the amp, and I really, really don't want to do anything destructive with the factory harnesses.You'll have to excuse my ramblings below; I'm just trying to be as thorough as possible.No one has had a simple answer for how to bypass the amp right there under the seat using the existing wiring and harnesses. I think there is a simple answer, but I wish I knew for sure it will do what I think it does: the Metra 70-2056. You probably didn't know it exists; it's not on Metra's website or in their regular catalog. But the shop I was at had another Metra "applications" catalog with some esoteric stuff in it, including the 70-2056. (autotoys.com has it, but it's grossly overpriced) From the picture, which of course is not big enough for a close evaluation, it consists of two separate harnesses with very long wires (long enough, I assume, to reach from under the seat to the head unit). I know for a fact that the wire harness coming from the receiver uses the exact same harness as used on the other end: the 70-2003. So I assume that one of the harnesses is just the 70-2003 with really long wires. The other harness appears to be the long-needed harness for the speaker-outs from the amp.I'm tempted to shout out "Eureka!" But I'm not 100% sure this is what I need. First, if all you need to do is splice these two harnesses together under the seat, why the heck are the wires so long? Or for that matter, why doesn't Metra just sell them already spliced? The long wires seem to indicate that it's meant to be run from somewhere (under the seat, I assume) all the way to the dash. But then, why would you need two harnesses? If you wanted to rewire for the speakers, all you would need is the harness for the speaker-out connection and then run that to the dash to splice it with the harness from your receiver. Am I making sense? Because this amp bypass kit isn't. I'm wondering if the other harness is maybe the inverse of the 70-2003, so that you can run that to the dash and then buy another Metra 70-2003 to splice normally with your receiver harness. ??? This just doesn't make sense. Why would you do that when the wires are already there? The easiest possible way to bypass the amp is just to do it right there under the seat! Why the long wires? Aaaahh!Please shed some light, someone. Otherwise, I guess I'll be the one to make the $35 non-returnable purchase and find out if this is what we need.

[Mr. Poopypants]

I wish I knew because that sounds like something I would be interested in too.

[lazytiger]

There are a few more things to consider here, I think. First, there's no way of knowing if the thing actually looks how it does in the picture. Second, the kit is for more applications than just the Vibe (also for '00-'02 Suburban/Tahoe/Yukon, '04 Bonneville, and '04 Grand Prix), so it's possible that the long wires are for a different vehicle. Third, there are more wires at work here than just the speakers - ground, power, turn-on, etc. So who knows where all these wires need to go. Although, nothing but the speaker wires are needed after it has been bypassed. So, it still seems like there should be a simple way to bypass the amp.I have another observation, too. After searching through this forum, I came to the understanding that the M&T amp has some sort of built-in crossover for the tweeters. But I just looked at the amp again a minute ago, and there are only 4 speaker outputs, not 6. So the tweeters must be wired through the front speakers and crossovers of some sort must be in the doors. That sucks, because I had a vision of putting the crossovers for some aftermarket tweeters under the seat. Can anyone confirm that the tweeters are wired through the front speakers and have crossovers in the doors?There also seems to be conflicting information about whether the stock speakers are 4 ohm or 2 ohm. They use a 2 ohm spec for the amp on paper so that they can say it's 200W. But if the speakers run at 4 ohms, doesn't that cause the amp to run at 4 ohms? Or can it only run at 2 ohms? We need a lesson in electricity, here. And what's happening right now, electrically, when I'm running my speaker-level, 4 ohm load from my Alpine receiver to the supposed 2 ohm M&T amp and supposed 2 ohm speakers? What if the speakers are actually 4 ohm? Aftermarket ones certainly are, so just assume I have aftermarket ones. I read somewhere in this forum that running an aftermarket receiver with the stock 2 ohm speakers will slowly ruin the receiver. True?All I know is, my Alpine used to sound awesome in my Civic and now it sounds pretty crappy in my Vibe (definitely worse than with the factory head unit). And I'm placing all the blame on the M&T amp.

[Jahntassa]

M&T speakers are 2 Ohm, I believe all other systems are 4 Ohm. The Nav system's tweeters are wired in line with the front door speakers with a cap on each tweeter. According to the information from the wiring diagrams, the M&T amp has a built-in crossover for the tweeters. Where do you see four ouputs on the M&T amp? And yeah, the amp is probably causing your issues.

[lazytiger]

Quote, originally posted by Jahntassa »According to the information from the wiring diagrams, the M&T amp has a built-in crossover for the tweeters. Where do you see four ouputs on the M&T amp?I'll have to take a picture for you soon. For now, all I can tell you is there are two harnesses coming out of the M&T. One has quite a few wires and, though I'm not sure if the wires are on the correct pins, the 70-2003 fits onto it. I assume this is the harness coming from the receiver. The other harness is the more square-ish one with big metal contact points. I assume this is the speaker-out harness. There are only 4 pairs of wires coming out of this harness. There has to be more wires going IN that OUT, right? So this is the only way that makes sense, unless the speaker OUTputs are on the same harness with the power, ground, turn-on, mute, and sensitivity wires... that would seem a little strange, no? I don't know what to say about that schematic for the amp. I'm looking at it right now, and it is clear as mud as far as what is on what harness.Also, the amp install kit I bought (for my sub) came with a 30 amp fuse, but the amp manual calls for a 25 amp fuse, and I see on the M&T schematic that it also uses a 25 amp fuse. Is that an important difference? Should I get a 25 amp fuse?And... I'm in email contact right now with Metra's tech support. Hopefully I'll get the questions about the 70-2056 cleared up. I'll be sure to post everything I find out.

[Mr. Poopypants]

I need to bypass the M&T amp badly, my system could perform like a mother, but the M&T amp is not allowing me to adjust the sound as much as I would like. I can only adjust things so much before I get distortion.

[lazytiger]

Well, what I can tell you so far is that the tech support guy said that the 70-2056 is supposed to run from the speaker harness under the seat directly to the harness on your receiver. Which I take to mean that there's only one harness, even though the picture shows two. He says there isn't a harness that just jumps from one harness to the other under the seat. My problem is (see previous post) that I'm not sure which harness is the speaker output. If the 70-2056 comes with the square harness, why couldn't you just buy a 70-2003 also and then splice them together under the seat?I just sent a reply email back to Metra. I'll let you know when I get a response.

[Mr. Poopypants]

Please do let me know, I would buy both adapters if it would help solve my problem easily.

[lazytiger]

If anyone can answer for us which harness is the speaker output, we can figure this out right now without waiting for the Metra guy to get back to me (though his first response was very timely). If the speaker output is the square one, we're in business. If it's the rectangular one with more wires, we're screwed. Well, not screwed, but it won't be a simple plug 'n chug under the seat.

[lazytiger]

Of course! What fun would an OEM interface be if it wasn't a pain in the (removed)?! Here's the latest word from the Metra tech guy:Quote, originally posted by Metra tech support »You have to plug into both harnesses under the seat and run those wires back to the radio. You do need both harnesses. That amplifier is not set up with one input harness and one output harness. Both the input and output wires are split up between the two harnesses. You can not just jump the wires from input to output because there are more output wires than input wires.So, simply put, there is no easy way to bypass the M&T amp. At least with this Metra kit you don't have to chop up any factory harnesses or run new wires all the way to the speakers. Unfortunately, it still involves running new wires to the amp harnesses. If Metra can't think of a better way, then I imagine this is it. Sigh... I guess I'll do it. I still don't understand exactly how this is going to work, but it's clear that any way I want to do it, I'm gonna need this kit.Anyone else who's considering doing this, don't buy it from autotoys.com! They want almost $60 for it! The guy at the store I go to said he would get it for me for $35, and I imagine I won't have to pay any shipping. Ask your local dealer!

[ragingfish]

Quote, originally posted by lazytiger »Installing my Alpine went so smoothly that it's emboldened me to try installing my sub and amp, too. But I also need to take care of the problems caused by the M&T amp. The sound simply isn't very good since I installed the Alpine; there's lots of background hiss, and it's way too loud. The volume increments are absurd. 0 is off, 1 is too loud for background music, 2 is about right for normal listening, it really starts to blast at 3, and I haven't dared to turn it up past 4! I'm sure it would start to blow the factory speakers at 5 (I can't even fathom turning the Alpine up to its limit, which is 30!!). Your problem is this.You're double-amplifying your signal.It's first amplified by the head unit. It's then sent out via the main harness to the M&T amp, where it is ONCE AGAIN amplified. I had this same problem when I installed my HU at first. It's an easy fix. Go to walmart, grab one of these for $15: It may be under the model numbers SLC-4 or FAI-3A. Either way, how it works is, you connect the head unit's output to one side, the metra harness to the other side. Adjust each channel to suppress the output of the stereo. That way, you're basically sending a low level signal to the amp which is then properly amplified. I've been using that and it works like a charm. It's much easier then bypassing (or even attempting to bypass) the M&T amp. IMHO anyway.However, should you decide to bypass the amp, here are the pinouts for the amp:AMPLIFIER C1 24-pin connectorA1 - BLK/WHT - Sensitivity ControlA2 - Not UsedA3 - BLK - Ignition Positive VoltageA4 - BLK - Left Rear Audio Input (+)A5 - YEL - Left Rear Audio Input (-)A6 - PPL - Left Front Audio Input (-)A7 - PNK - Left Front Audio Input (+)A8 - WHT - Mute ControlA9-A12 - Not UsedB1 - WHT - Right Rear Door Speaker Output (-)B2 - RED - Right Rear Door Speaker Output (+)B3 - Not UsedB4 - WHT - Right Rear Audio Input (-)B5 - RED - Right Rear Audio Input (+)B6 - LTGRN - Right Front Audio Input (+)B7 - BLU - Right Front Audio Input (-)B8 - Not UsedB9 - RED/WHT - Left Front Door Tweeter Output (+)B10 - BLU/WHT - Left Front Door Tweeter Output (-)B11 - GRN/WHT - Right Front Door Tweeter Output (+)B12 - BRN - Right Front Door Tweeter Output (-)AMPLIFIER C2 8-pin connectorA - LTGRN - Right Front Door Speaker Output (+)B - BLU - Right Front Door Speaker Output (-)C - PPL - Left Front Door Speaker Output (-)D - PNK - Left Front Door Speaker Output (+)E - BLU/RED - Battery Positive VoltageF - WHT/BLK - GroundG - BLK - Left Rear Door Speaker Output (+)H - YEL - Left Rear Door Speaker Output (-)Quote, originally posted by lazytiger »Also, my one idiot move of the night - I dropped one of the screws connecting the receiver to the dash down in the dash. How do I take apart the lower dash to try to get it out? Unless it rattles though, I'm not sure I care a whole lot. The receiver seems rock solid with only two screws holding it in.You can find a detailed walkthrough on removing the center console here:http://forums.genvibe.com/zerothread?id=5940I had the same problem when I installed my head unit.However, the unit may seem solid, but I guarantee you it will rattle. I had mine held in by 3 bolts for a while, and it still rattled horribly.My advice, get some new screws either from GM (part #94858270 for 1 each) or see if your local auto parts store can match it for you.

[lazytiger]

Thank you for that info, Ragingfish! It is much appreciated. I've seen that Scosche thing in a different thread here, and I know it's a viable option. However, I figured that if I ever want to replace my factory speakers (which I do), it would be better to use the receiver's amp rather than the M&T amp. You know, the whole 2 ohm vs. 4 ohm thing. In my warped little mind, the line-level adapter seems like the "make do" solution, whereas bypassing the amp is the "real" solution. I know, I know. It's mostly just because I'm crazy.I still believe that I might be able to rig the bypass under the seat using the Metra 70-2056, with the help of the pinout info you provided. So a very, very huge thank you. The one thing that concerns me about splicing under the seat is, what happens with the unused wires? Specifically the amp's power wire. Is it safe to just leave that unhooked, or should I find out where that goes and disconnect the other end of it? And I'm still trying to figure out why, if it's possible to do it under the seat, Metra expects you to run new wires to the dash? Well, I'm going to go ahead and order the 70-2056 today on my way home from work. I don't know how long it might be before I get it. But I will certainly post my results in the forum.

[ragingfish]

Quote, originally posted by lazytiger »The one thing that concerns me about splicing under the seat is, what happens with the unused wires? Specifically the amp's power wire. Is it safe to just leave that unhooked, or should I find out where that goes and disconnect the other end of it? It's likely tied up in half a dozen harnesses...you'll never be able to "unhook" it. If you cut it out of the connector, just leave it without an end, stick a wire nut over it, then electircal tape the nut onto the wire so it won't pop off. If you're not even plannign to remove it from the connector, just put some tape over the connector.Either way, I doubt you'll have a problem.

[rudolph]

Apparently some people are connecting the speaker outputs of their new head unit to the M&T amp and getting too much amplification. Has anybody experimented with the "Sensitivity Control" wire (pin B6 in the dash harness)? Does anyone have the official spec on how that wire functions? If you connected it to the center arm of a 100k variable resistor that goes between +12v and GND, could you adjust the amp so it doesn't boost the signal so much?

[rudolph]

To answer my own question, I measured the voltage on the "Sensitivity Control" pin without the factory radio connected but with the amp powered up. It said 5v. I connected that pin to +12v and GND, first through a resistor then a straight connection, and it didn't have any affect on the gain. Maybe it's some kind of digital input. Never mind.I really wanted to avoid cutting wires under the passenger seat, but I didn't like how my new radio sounded being double amplified by the Moon and Tunes amp. I also didn't want to pay a lot of money and wait around for the 70-2056 connectors to bypass the amp. First I dismantled the amp and tried to snip out the male connectors from it. The 24-pin connector fell apart when taken off the board. I managed to get the 8-pin connector, but by then I finally decided to get over my psychological resistance to cutting the wires under the seat. There's plenty of wire to work with down there, so I looked at the wiring diagrams and started cutting. They simplified the wiring colors in my Vibe. The audio inputs for my amp were:A4: LR+ BlackA5: LR- YellowA6: LF- PurpleA7: LF+ PinkB4: RR- WhiteB5: RR+ RedB6: RF+ GreenB7: RF- Blueand the audio outputs from the amp to the speakers were the same colors! I cut those pairs of wires from the connectors and spliced things together. I left the tweeter wires and all the other power/control wires uncut on the connectors, then taped over the connectors to prevent any possible shorting under the seat. The results sound great with my new CD/Cassette/MP3 player.If anybody wants the 8-pin male connector from my amp for mating with the 8-pin connector under your passenger seat, let me know, but I tell you it's easier to just not worry so much about cutting the wires under your seat.Behind the dash, the only thing I had to do besides getting the standard GM adapter cable was to connect pin B3, which is the amp and antenna-amp turn-on signal, to my radio's power-antenna output, in order to get radio signals from the amplified antenna.