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2005 chevy
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6,469 Posts
Discussion Starter · #1 ·
I want to wire up some LEDs behind the speaker grills in each door, but not sure which wires to tap. I checked the wiring diagram under the resources section but that didn't quite lay things out as I'd hoped. I've run a few searches, and came across some schematics of the wiring, but still can't tell what all wires control which functions.

I grabbed my meter, disconnected one of the harnesses in a rear door and took some measurements with the truck off, finding a constant 12V and 9V source. When starting the truck I got 14V on both, no changes on the rest. (although I'm sure I didn't check all combinations) :bonk:

Not really sure what's what, so I'm hoping someone has (or knows) what the pin assignments are in each door. Obviously I don't want the lights on when the truck is turned off, so unless I missed something, I'll have to use relays with something else... Maybe the window switch light wire? :undecided

Anyway, if anyone can point me in the right direction, I'd really appreciate it!
 

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2002 chevy trailblazer_lt
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192 Posts
i would suggest run a power wire from a switch into the door. get your power for the switch from ignition( pink) or acc ( orange or brown) at the ignition harness. those will only be on when the truck is on but you could still shut them off buy the switch. if you had to you can use the 12v at the power window switch but i think the above option is best in the long run. hope this helps
 

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2005 chevy
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6,469 Posts
Discussion Starter · #4 ·
If you want them dimmable like the lights behind the buttons on the door, that wire is available. I'll look it up if dimmable is an OK alternative.
I didn't know those lights were dimmable, although I never paid attention to them when I've turned the knob on the dash. That would be cool if you could tell me which wire that is, sounds like that's just what I'm looking for. :yes:
 

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2004 gmc
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Sorry, I was without my manuals yesterday.

I misremembered some research I did a few months ago for a similar question. The REAR door switches receive a dimmable lamp supply wire from the BCM, brown/white, on their 8-pin connectors. There is no intelligent control module in the rear doors.

In the front doors, both sides have an intelligent control module (DDM and PDM), and the dimming is controlled locally, within the module, by a serial data message from the BCM. So the doors are just slaves, and it saves a couple of wires in the harness, for GM to do it this way. Since the PDM and DDM are fed with unswitched 12V, there is no accessible wire that's hot only when the ignition or lights are on. You'd have to backfeed your LEDs from the door module switch lamps, or snake a wire from the vehicle through the door hinge boot.
 

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Banned
2005 chevy
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6,469 Posts
Discussion Starter · #7 ·
It's all good man, it was a holiday yesterday after all, you deserve a break! Sounds like my idea is going to be more complicated than I wanted it to be. Guess I'll bump that one down the mod priority list a few spots.

:thx for looking into it for me though.
 
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