Forum Discussion

BobsYourUncle's avatar
Feb 02, 2017

Lost power to drivers door functions - need diagram

TV in sig, 2007 Classic GMC 3500 dually, 326,000 kilometres, over 200,000 miles on it.

I have lost power to most everything in my drivers door.

The only thing I can do is control the drivers side mirror only. Can't control passenger side. And the speaker works.

Everything else is dead. No window control, no door locks, no in door light when I open the door, nothing. No remote lock / unlock of drivers door.
The sensors that detect the door being open are dead,
My alarm system notifies me the door is open when it isn't.
The dome light was staying on and I could only use the dash button to turn it off. Today the dome light is off on its own, but won't come on when I open the door.
Yesterday when this whole condition started, the key in ignition chime would sound with the door shut. Today it doesn't.

I need to find a wiring diagram that shows the door circuits and where they all go etc. Need to read it and learn where the power comes from and where it goes in the door so I can trace it, probe it to find a break.

Without overlooking the simple, I don't believe that each door electrics is fused individually. I think that if you lose power to the windows or door locks, it's all or nothing. I could be wrong.
The passenger side door controls work fine.

I strongly suspect that there may be a break in the power feed wire to the door electrics. And I suspect it may be inside the rubber tunnel that goes from the body to the door. Reason I suspect this is that the truck is 10 years and 4 months old and in constant use. Doing a little simple math estimating the door opens and closes at least ten times a day, likely a lot more, indicates that the door has opened and closed 40 to 50 thousand times in its life so far.
This means that rubber thing with a mittful of wires has seen enough flexing to perhaps cause a wire to break and lose contact.

Anyone here up on or familiar with the electrics of a truck like mine?

In my younger years I have rebuilt wiring in old cars, troubleshot many many wiring problems and fixed them so I'm no stranger to this.

But I do know and understand that with the computer controlled everything, there are single wires that will feed a number of circuits depending on impedance, load, voltage etc.

If anyone knows where I can either download or just view a schematic, I'd appreciate that info, thanks.

Also, anyone know if the door harness is modular? That is, does it plug in to the main harness or terminal block so it can be removed for replacement or repair. I may have to pull it out to chase the power wire to locate a break.

Sorry for the short novel...:B more info is better!
  • Google search indicated that the most common cause of this is the switch module, followed by a broken wire.
    Good luck.
  • I would be focusing on the bend point in the wires going from the truck to the door. Disconnect the battery and do some continuity checks on those wires from one end to the other. The intermittent failures you are seeing would match a broken wire at the bend point. One time there is enough connection and the next there is not.
  • I believe I have the same truck and had the same problem a few years ago.
    My entire switch module got wet during a heavy rain. I was camping trying to get parked in a downpour. I was trying to avoid getting the entire combo stuck in the mud. Drivers door was open during the downpour allowing switch module to get wet I digress....
    Anyway entire switch module had to be replaced. $250.00 or so for the part..ouch
  • Thanks for the help guys.
    I'll try the battery disconnect thing, it's a he cheapest! Along with the extra ground.
    I doubt it's the switches becaus it all failed at the same time. However, if the power goes to one switch before the others it could be a continuity problem.
    I'll have to get in there with a probe on the hot side of the switches to see.
    If I had a schematic I hat would help. Maybe I could stop by a dealer and get a copy.

    Thanks
  • j-d's avatar
    j-d
    Explorer II
    Just for quick and cheap, connect a ground wire from the door to the truck body. With the way the hinges and latches are made, the door is not inherently grounded to the vehicle so door function wiring requires a ground wire. I've fixed problems by adding a new ground wire, so I'm saying Worth A Try.
  • Those switches fail often. Hope it's not that. They are pricey and must be programmed after install. They are available now in the aftermarket at least.
  • large orange wire seems to be the power source to the door and a common problem.
  • Maybe this will help Link
    Some are saying disconnect the battery for 1/2 hour. It's worth a try.
    Good luck

About Technical Issues

Having RV issues? Connect with others who have been in your shoes.24,194 PostsLatest Activity: Jan 29, 2025