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Ignition power under the hood

Posted: Thu Mar 06, 2014 7:39 pm
by Thunderscreech
I've got some light strips (the kind with a bunch of tiny LEDs) that I want to outline my headlights with, but I'm having trouble figuring out how to power them. Full time power is out, obviously, and simply wiring them to parasite off the headlamps doesn't work for me because I'd like them to be on independently.

I was thinking that the almost ideal setup would be that they get power when the ignition is on, but I'm running into some challenges finding a good line to tap under the hood for this. Can anyone suggest something to use? I could pull from a line behind the dash and go out the grommet if I have to, but I'd rather not for this project.

Thanks!

Re: Ignition power under the hood

Posted: Sat Mar 08, 2014 5:03 pm
by Thunderscreech
From the silence and my failure to find inspiration under the hood since I posted this, I'm growing increasingly convinced that I'm going to need to tap a line in the cabin and run a cord out the grommit. If anyone has any other ideas, or even if I'm lost, wants to put an idea down for someone asking the same question the future, that'd be cool. :)

Re: Ignition power under the hood

Posted: Sat Mar 08, 2014 9:18 pm
by Chiadog
I'm guessing not a lot of Vibers have looked for auxiliary power under the hood - I know I haven't. I'd suggest you get a wiring diagram before you dig into your Vibe. That being said, my crappy and OCCASIONALLY CORRECT Haynes manual shows a constant power supply to the windshield wiper motor via the solid blue wire -YMMV!
Good luck and give us some pics when you are done.

Re: Ignition power under the hood

Posted: Sun Mar 09, 2014 7:55 am
by joatmon
I've never needed one, but I'm sure there are more ignition switched 12V lines under the hood than these
Yellow wire at alternator
Red wire feeding park/neutral switch ( wire might still be there if you have a 5 speed)
black wire w/ white stripe feeding ignition coils

You want to verify those in your car before you take my word on it and start cutting/splicing wires.


The thing to keep in mind when picking up an existing wire and putting an additional load on it is to be absolutely sure that the added circuit is secure, sealed and mechanically survivable, and that the extra load on the circuit can be handled by whatever feeds the source. You don't want a splash of water or a hard bump, or a short in your added wiring to take out ignition, charging, regulation of the tranny, or some other critical vehicle subsystem.

Re: Ignition power under the hood

Posted: Sun Mar 09, 2014 9:15 am
by Derf
joatmon wrote:The extra load on the circuit can be handled by whatever feeds the source. You don't want a splash of water or a hard bump, or a short in your added wiring to take out ignition, charging, regulation of the tranny, or some other critical vehicle subsystem.
Other than the wires for the marker and headlights not sure what source is available. When I added items to the car, ran several spare wires through the firewall. Just created a pigtail fuse to feed the attached item from open spots in the fuse block, above the brake pedal. Even with a nearly loaded Vibe, their were still a lot of openings on switched power in the fuse block. If it warms up today may take a picture.

Re: Ignition power under the hood

Posted: Mon Mar 10, 2014 4:03 pm
by Derf
The top is toward the firewall. You can see the 5amp and 15amp fuses with wires soldered to one leg of the fuse. Both these locations on the 2005 were switched power, the 15 amp was for the CIG plug, tapping this does not impact any critical systems, just your 12v power port next to the shifter or in the console. Make sure to tap on the load side, otherwise you will be hooking directly to the main switched power in the fuse block. The 5 amp fuse shows nothing in the manual, empty spot (Matrix use?) In the Manual, under the hood the only safe spot I see tapping into is the one called "Amp", runs the Moons and Tunes if equipped. Take out this fuse and your radio goes silent.
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