2008 Yukon door lock/electrical problems

seminole · March 5, 2015

I have a 2008 GMC Yukon that seems to have electrical issues. When we hit unlock sometimes all the doors will unlock and sometimes only a couple will. I have read numerous forums in which the owners with same issues took it to the dealership only to have the actuators replaced on the ones not currently working. Most said they ended up with the same problems with the new actuators. My cruise control also randomly works.

It sounds to me almost like a ground that is constantly moving. When it touches everything works.......any ideas?

Doug_Scott · March 6, 2015

This can be a couple of things. Is it always the same locks that fail? If so, can you predict when they will not work? If so, have someone sit next to that door, and just before you press the unlock button, have the person lightly lift up on the lock button on the top of the door panel. If the lock seems to work better than normal when you do that, then the latch or the actuator is not lubricated and harder to move than normal.

If that makes no difference you are going to have to remove the door panels on the doors that do not always unlock. Once they are apart, pull the wire connector off the actuator and test for power while moving the pwr lock button on drivers door to lock and unlock. Does it always have power when the switch is moved? I do not know how many wires are on the actuator, or even what wires to test for power. My best guess would be that there are 2 or 3 wires. If 3, I would expect one to be a ground, one to be unlock, and the third to be unlock. If 2 wires, one would be for lock, and the other for unlock, with ground being handled by mounting actuator to metal door panel. It may also be that the polarity is reversed on the actuator to get lock and unlock with two wires. If it done this way, when locking, one wire will have power, the other ground, and for unlocking, the wires are reversed, power wire becomes ground, ground becomes power for example.

If none of that works, and you are adventurist, find a 12 volt LED, and wire the ground side to ground, and the input wire to one of the wires on the actuator. You should be able to run the wire past the door panel so you can see the led every time you try to use the pwr locks. If the led does not work, then you have a power issue at the actuator. I know this sounds like a lot of work, but it really isn't, and if you cannot get the pwr lock to fail while working on it, doing this will allow you go back to using the truck and hopefully find what is causing the locks to fail.

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Keep in mind I have no hands on experience with power locks on our trucks, this is just how I would think it works. Use a voltmeter to check for power and grounds.