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2004 Envoy The lights don't come on when the front passenger door is open. They come on when All the other doors are open. I'm sure it's just a bad switch in the door but where is it located?
 

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There is no electrical/mechanical door switch for the light. The dome light is controlled by the Body Control Module (BCM). When the door opens, the BCM is signaled somehow and subsequently the BCM commands the dome light to turn on, and when the door closes, it (the BCM) commands the dome light to turn off.

I am not sure what in the door is responsible for "signalling" the BCM. Perhaps @TJBaker will chime in as he knows more about the BCMs than I do.

Good Luck!
 

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There is no electrical/mechanical door switch for the light. The dome light is controlled by the Body Control Module (BCM). When the door opens, the BCM is signaled somehow and subsequently the BCM commands the dome light to turn on, and when the door closes, it (the BCM) commands the dome light to turn off.

I am not sure what in the door is responsible for "signalling" the BCM. Perhaps @TJBaker will chime in as he knows more about the BCMs than I do.

Good Luck!

Partly correct. No door switches are wired to any lighting circuitry. There are door jamb switches though. And the trouble here could very well be the passenger door switch. I suppose it could also be a PDM issue but if the rest of the PDM is functioning then the switch or some loose wiring seems more likely.

So how does it work? The front doors each have their own dedicated modules. The two rear doors are controlled by and wired to the BCM. If a rear door is opened the respective doors jamb switch activates and the BCM sees this directly and issues a series of network messages resulting in various actions taken by numerous vehicle modules plus the BCM can directly control a number of lighting circuits.

In the case of a front door opening the respective door module sees this as they have their own door jamb switches wired to them. That module then issues a network message indicating the door is now open. The BCM sees these messages on the vehicle network and the BCM is programmed to take certain actions when it sees these messages and both turn on lighting circuits as well as issue network messages that are seen by various modules who then might take actions of their own to enable or disable their own display lighting etc. Clear as mud, right? Nothing is simple anymore.

Rectangle Slope Font Line Parallel
 

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2004 Envoy The lights don't come on when the front passenger door is open. They come on when All the other doors are open. I'm sure it's just a bad switch in the door but where is it located?

So where is the door switch actually located? I have no idea!! I would assume it is inside the door connected somehow to the arm the extends from the door jamb into the door?
 

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TJBaker, I am glad you do not know where those darn things are either!
 
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There is no electrical/mechanical door switch for the light. The dome light is controlled by the Body Control Module (BCM). When the door opens, the BCM is signaled somehow and subsequently the BCM commands the dome light to turn on, and when the door closes, it (the BCM) commands the dome light to turn off.

I am not sure what in the door is responsible for "signalling" the BCM. Perhaps @TJBaker will chime in as he knows more about the BCMs than I do.

Good Luck!
I think the HVAC module senses the change in internal pressure when the door is opened ---- 'tis a mystery.
 

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Actually - as I was Googling it, I remembered seeing that switch inside the door of my 05TB.

But let's play this for a while --- anyone wanna guess?
 

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OK, is the switch activated by the linkage that connects the door handle to the latch?
 

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Ah hah!
 

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Thankfully, mine is OK --- but the lock actuator - (lock UN-actuator, really) .... on my TB is dead.

IIRC --- you can lock the door even if the battery is disconnected by the key or manually operating the individual lock toggles on each door ..... but .........

If you have a dead battery or the keyfob is INOP and you try to use your PHYSICAL key to open the driver's door (where the ONLY keyhole is, BTW!) ---- you cannot open the door because you still need battery power to activate the solenoid to unlock the door.

I have a workaround for this .... about which I am creating a video to air as soon as I get a good recording and before the next snow.
 

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Regarding your workaround - is it taking a .357 Magnum and shooting the lock to holy smithereens?
 
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I recommend everyone connect that mystery red wire up at the battery. It is a direct line back to the 7 pin trailer connector. You can use that to get enough power into the system to unlock the door. In the case of my own early 2002 LT model it's fairly easy to pop the hood open with a thin long blade screwdriver though the grille though.
 

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Actually, a great idea! In my case, I think I am going to make up a a "jumper" with ring terminals on one end and a pair of 45 amp Anderson PowerPoles on the other end, and then install that because all my radio gear that operates on 12 VDC is equipped with PowerPoles already as are my 12VDC power supplies and jumper packs.


And, if worse comes to worse, I can always use a couple of cheap alligator clip leads.
 

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S&W, Glock, Walther, or Beretta, you get the idea :cool:
 

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I built a 7-pin male plug that fits into the trailer connex with red and blue wires hanging out of it and some spade connex on the ends. I can also use it to run a small winch from the vehicle battery for when I collect firewood.

It works - winch-wise .... I've used it a lot already.
 
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