Planning to fix A/C - need advice

Technical info on the Pontiac Vibe and Toyota Matrix including do-it-yourself info
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freed
Posts: 9
Joined: Thu Jul 15, 2021 12:09 pm

Planning to fix A/C - need advice

Post by freed »

Hi folks,

I just bought an '06 base Vibe and I'm stoked! It needs a bit of TLC, which I have been providing. On my list is fixing the A/C — the previous owner just did without for 8 years(!). I live in Seattle, so typically it's not necessary, but given the heat waves we've had recently, it may come in handy.

I'm hoping it's as simple as replacing the AC clutch, but need to do some more diagnostics to see if it does have power. I verified it's not clicking on when the AC is set to run, and the blower does work.

Anyway, my main concern is this: assuming that replacing the clutch fixes the system, would there be any danger in running it? Or should I do some more maintenance on other components to avoid damaging them? It's possible there's a leak & the refrigerant has bled out, but if I understand correctly, the low pressure cutoff would prevent the AC from running in that case.

Advice welcome!
andrewclaus
Posts: 481
Joined: Tue Oct 03, 2017 6:38 pm
Location: Golden, CO

Re: Planning to fix A/C - need advice

Post by andrewclaus »

Based on very limited experience with another old car, I'd try this:

Pull the relay and check the coil terminals in the socket for voltage (ignition on, A/C switch on, blower on). If there's voltage, bench test the relay, or swap for another if there is one. If the relay doesn't have voltage to the coil, try jumping the pressure switch. There's also a thermistor at the evap coil giving input to the ECM, which controls the relay. That can be checked for open circuit. If the only problem is the pressure switch, then check refrigerant pressure and add if needed. You may want to get a pro to do this and check for leaks.
freed
Posts: 9
Joined: Thu Jul 15, 2021 12:09 pm

Re: Planning to fix A/C - need advice

Post by freed »

Ok, thanks! I understood most of that, lol. And can figure out the rest. I used to fix laundry machines for a living, which involved a lot of this sort of thing...

So basically, as long as the parts are working and the refrigerant is charged & not leaking, I should be good to go? I think I need to look at a basic text about how A/C systems work, cause I don't fully have that in my brain. Still just worried abstractly about damaging some component if I resurrect the system from a long sleep.
andrewclaus
Posts: 481
Joined: Tue Oct 03, 2017 6:38 pm
Location: Golden, CO

Re: Planning to fix A/C - need advice

Post by andrewclaus »

Since refrigerant oil hasn't circulated in years, seals may be dried out on some expensive parts, but hopefully not. Just getting it going shouldn't damage anything, except for loss of refrigerant if there's a leak. The pressure switch is a monitoring device to keep it from killing itself. The thermistor mentioned above looks for ice buildup in the evap coil.

I'm not a HVAC tech but I still work on them (and washing machines), mainly the power and control systems. It's a pretty simple system. As liquid refrigerant evaporates in the evaporator coil in the cabin, it takes heat out of the air, just as water evaporating off your body after a shower feels cold. It condenses again in the condenser coil at the radiator, essentially pumping the heat from the cabin into the engine compartment. The compressor helps things along.

If you get it going, check the condensate drain from the evap coil. If it's plugged, you'll get a wet carpet and moldy odor. Good luck.
freed
Posts: 9
Joined: Thu Jul 15, 2021 12:09 pm

Re: Planning to fix A/C - need advice

Post by freed »

Awesome, thanks so much! Now, to find time in my schedule...
KingKrab65
Posts: 162
Joined: Wed May 24, 2017 7:25 am
Location: Charlotte, NC

Re: Planning to fix A/C - need advice

Post by KingKrab65 »

Like has been said earlier, check for leaks in the system. The system not running for years can make the seals dry out and leak when no oil is being run through the system. Also, if there is an opening in the AC system, there could be moisture inside of it potentially making components rust. I had this happen on my old Paseo and ended up replacing just about all the seals and several major components.

I am not sure if it is available any more locally for where you live but there is some refrigerant that has dye in it. You can get a cheap UV light at Harbor Freight for the tracking down any leaks after putting in the dye. Putting it in made it easier to check for leaks and it also can stay in the AC system as a charge.

https://www.amazon.com/Johnsens-R134a-R ... B086Z4FF5N

Also, most major parts stores have refrigerant gauges to "borrow" unless you really feel the need to have one in your tool box. :)

Good luck with your AC project.
2003 Base Vibe
freed
Posts: 9
Joined: Thu Jul 15, 2021 12:09 pm

Re: Planning to fix A/C - need advice

Post by freed »

Thanks so much KingKrab! Great advice here.

I'm moving this weekend, gonna try knocking out a speaker upgrade this morning while I'm still close to my dad's shop space. The AC is on my list along with spark plugs...will hopefully find some time in a weekend or two. Full-time work has got me slammed lately!
FlyHappy
Posts: 4
Joined: Fri Jul 16, 2021 5:57 pm

Re: Planning to fix A/C - need advice

Post by FlyHappy »

freed - did you get after that AC yet?

I just wanted to check that you really, truly are certain that there's a deeper problem with the AC outside of simply low R410a. Did you pressure test it with a proper manifold or something?

Ready for a long story?
I bought my 2003 GT new off the lot in 2002 and drove it, disinterested for 10 years; I had stopped wrenching on my own vehicles and turned that over to pros while I raised a family. Eventually, the blower motor began to get unreliable.... just randomly stopping and starting in any and every position. The AC would always light up and when the blower chose to blow, I'd get cold air.... until I didn't.

At this point, the car is 15 years old, a little beat up (blame my kids), and I'm already pondering a replacement, deferring repairs, etc.
Oh... and I live in Minnesota where it actually does have a short, but hot summers, and the Winters are no joke. The last 4 winters I've had heat blowing less often than not. One day, my dash starts playing the drums, and I mean LOUD.... WTH? (yeah, it's the infamous recirc actuator, though I did not know at the time). I find I'm like the Fonz, and I can give the dash a good whack and make it stop, for a while.

So then a divorce comes around, COVID comes around, and golly if I don't fall in love with the boring car I've been driving for 19 years. So, I strap on the tools - new blower motor, new blower resister, check harness connection, test ground.... blower is more consistent, but not fully. Decide to get after that knuckle busting actuator, and even went to the extent of removing the passenger seat to give me a slightly less destroyed body while I work on it. 3 trips to the hardware store later (thank you top lag screw with the 1" of clearance), I've got it out and Mr eBay in - that flap valve works like a champ, and man do I like open the cabin air filter housing just to admire it in action.

Oh, did I forget to mention that cabin filter? Um....... like 5 pounds of tree detritus packed in there; yeah, there's a mesh screen above, but I guess 19 years of parking under a tree with Minnesota snow and ice packing everything down is too much for any car. (and another "why the hell was I paying mechanics?")

But still- got a blower thats super finicky, so eventually I find that stinking blower relay. that one not in the engine bay or the driver side, but way up under the dash, by the blower, which I'll admit isn't that unreasonable, but kinda unknown-ish. Pull it, and oh my.... nasty yellow stuff that looks like the back of my favorite greasy spoons flat top grill. Not Good Eats. A mere few dollars from Rock Auto, and Viola, that blower is humming solid, on demand.

Okay, so I've needlessly replaced a bunch of parts, and spents loads of warm summer nights with my head in weird places... but really - just having a ball, and all these parts are like $140 in total. Just further marveling at the magnificence of the 2003 GT , with its revvy motor, 6 speed gearbox, never stopping Toyota/Yamaha drivetrain, and the fact that I can literally put a 16' extension ladder *entirely* inside my car, with hundreds of pounds of tools and other materials - all doors closed. So why exactly have I been thinking of a Tesla for the last 4 years?

Now I move onto the AC compressor... I'm thinking clutch. That's what the cool kids say - I even call a couple of AC shops around and ask if they'd be willing to replace the clutch if I brought them the compressor. Lets just say I found myself thinkin I might know more about the car than they do (answer: "that can't be done, sir") . But first - let me test that solenoid on the compressor, just to make sure its operable if I manually put 12v on it, as would happen when the refrigerant pressure switch signals it. Yep - happy click, click to that. Hmmmmmmmm.... how about the refrigerant pressure switch itself, could it be bad? Sure, in theory..... mine isn't closing and sending 12v to the compressor solenoid, no matter how long I let the car run AC on, freshly repaired Air Handler blasting at Max......

Those $20 R410a top up cans can't actually do anything good, right? That stuff's for suckers who pour "Radiator Stop Leak" or Drano down the sink. Totally beneath me.

Well, ya know.... that can comes with a simple pressure gauge for the low pressure side; even if I'm not getting fancy with a pressure manifold it should give me a clue?
To the store I go - put that puppy on with the motor running and hey - there's some pressure... squeeze the trigger, burst, burst, burst... hmmmmm.. pressure increasing, I think that means no leaks? Pop it off, open the door... Holy Moly - it's blowing 60 degree or colder air while ambient temp is 90+.

Dang.
That was 4 weeks ago. Been really enjoying my chilly ride daily.

Oh, and while I have the dash wide open, that crappy GM/Delco head unit gets ripped out, and the touch screen Android head unit with Live Rear View and Screen mirroring needs to go in. After all, I had to remove the radio to assist in a two arm wrap around technique for the recirc acutator ;)

Annnnnnnnnnnnnnnnnd..... I've got the rear hatch plastic fascia pulled off to reveal the hatch lock, since it seized up and wont turn left a decade ago, not allowing me to use the fabulous opening glass feature (how many other subcompacts casually haul 12 foot Aluminum stock?) . While that skin is off, dang, that's a nice spot to drill a 20mm hole and pop that 720p rear view camera in. Oh, what about those hatchback lift struts? They're awfully weak in the dead of winter when the seals shrink and the gate is ominously moving towards your head.....

'Til next time....
tpollauf
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Joined: Wed Jan 20, 2010 11:37 am
Location: Toledo/Oregon, Port Clinton Ohio
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Re: Planning to fix A/C - need advice

Post by tpollauf »

Welcome to GenVibe ..... FINALLY :o Interesting life story, so far anyways. Glad you still own this reliable form of transportation! As a commercial/industrial refrigeration mechanic I HOPE you didn't put 410A into your Vibe. That's exclusively a mid temp refrigerant commonly used in comfort cooling AC systems (most homes & businesses since the mid 2000's). R134A is what you need. Hopefully it's a typo on your part. Keep us posted on other repairs and issues with your Vibe. Visit often1 ;)
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2009 Vibe GT (manual), 2009 G8Gt, 2009 Vibe GT (auto)
2014 Silverado, 2004 Vibe GT

"everything is modifiable"
freed
Posts: 9
Joined: Thu Jul 15, 2021 12:09 pm

Re: Planning to fix A/C - need advice

Post by freed »

FlyHappy, your story got me energized (heh) to try a few diagnostics tonight! What a great tale. Glad you got things working!

So on my 06 base: with the engine off, no key in the ignition, I tried rotating the plate at the end of the AC clutch. It does not move at all.

I tried pulling the relay (under the hood) and jumping the two terminals noted in another thread. Nothing, even with the engine on. I then tried checking for DC voltage across the same terminals. I got zero volts & same with the ignition on.

My next step is to find and replace the fuse (under the dash I take it) because it seems likely that it's blown, or I guess there could be a loose wire someplace.

If the clutch plate doesn't turn by hand, would that be fixed with a clutch replacement kit? Or do I need a new compressor?

While I was at it today, I installed a pair of new gas lifts for the rear lift gate. The old ones weren't popping up like they should. Quick and satisfying repair! Also did the cabin air filter, which was a little dirty.

I'm still waiting for a decent chunk of time to change the spark plugs, which are still original at 150k...got a torque adapter and everything...just nervous about the job. It'll be my first time getting that deep into an engine.
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