Power Liftgate Question

[ELVIS]

hi all,
I know this question has been beat to death and I have looked through some threads but I know basically whats wrong but I would like to broadcast the symptoms to you guys and get some feedback before I go buying parts. Liftgate will not respond to Key Fob, Rear handle, interior handle, or door switch. When pushed, nothing makes a noise in back at the motor but lights flash as normal and there is a click in the relay near the engine. Ive drilled an access hole at the dimple on the trim panel to get the door open as that is the only way. On the dash I get the 'Rear Access Open" signal and the rear wiper doesnt work as a result. I can open the liftgate window and have slammed it and still nothing. Based on this, what is your diagnosis...Actuator or motor, or maybe BCM issue. I wanted to mention also that the rear liftgate handle switch on the outside of the door failed about 2 months ago, but all the other options for opening the door worked. Its a 2008 tahoe, 5.3, Z-71, 150,000KMS ( Canada )

 

[NGAneer]

When you turn the power liftgate off inside the truck, it still won't open manually? If that's the case and you can't get it to unlatch, I'd say it's AT LEAST the actuator.

 

[ELVIS]

When you turn the power liftgate off inside the truck, it still won't open manually? If that's the case and you can't get it to unlatch, I'd say it's AT LEAST the actuator.

That's right, nothing happens when I turn the lift gate switch off. The lift gate does nothing and makes no noise. When I got the door open and slammed it shut again it was still saying 'rear access open'. Am I correct in assuming that the motor runs the actuator? If so, and there's no noise to indicate that the door is trying to open, I would think that the motor was pooched.

 

[NGAneer]

My gut would tell me that the actuator that opens the lock is frozen and in a place that is telling you the rear access is open on the DIC but won't allow it to open. I'd get the actuator/motor out of there and get a good look at it. Maybe you can troubleshoot it on a bench with a battery or you can check the voltage singles coming to it from the BCM.

 

[ELVIS]

Well....since it seemed to have no power to it I went out today after work to pull the trim panel and check all my connections. I pulled the negative cable from the battery for 5 minutes first to reset the system. I wasn't too optimistic that it would do much but as soon as I started the truck the rear door opened. So I guess the computer or whatever controls that had some demons needing removed. Thanks for your help.

 

[ELVIS]

Also the reason that the door would not open manually is because my door handle switch is pooched apparently so I will be getting another one of those.

 

[NGAneer]

Good deal. Glad it worked.