'14 Sierra Crew - RR passenger door open indicator always on

[2014highmiler]

'14 Sierra Crew 1500 4x4 5.3L 226,000kms - RR passenger door open indicator always on and RR window will not operate from the drivers position or at the RR door.



I've been reading this forum and all over the internet and have read to lubricate the door latch mechanism, replace the door latch mechanism, check for breaks in the wiring, reset BCM, replace drivers door switch assembly....



I just don't know where to start...



Any help would be appreciated.



JR

 

[winger870]

Start with looking for the easy fixes or cause. Lubricate the door latch, check for breaks in the wiring. If there is a break in the wiring they say it is usually in the wire at the door inside the rubber boot you see when you open and close the door. The wires usually break over time from fatigue from opening and closing the door.

 

[2014highmiler]

I managed to find a 900 page wiring diagram and have since begun to understand how the system works, which is actually quite complicated.



I disconnected the neg battery cable to rest the BCM and my door ajar issue has gone away, which is fantastic.



However, the window will not go down from the driver's or passenger switch.



As mentioned earlier, the rear window switches were swapped and this determined that the door in question's switcth would operate the window on the opposite side, but the switch from the opposite side would not operate the door in question.



So, that's where's things are at. I wouldn't think that a 2014 work truck rear window motor would be faulty as it would hardly have been used. However, I guess it's a possibility.



I guess the next step will be to test the window motor independent of the switch, but I will have to do some digging to find out which wires to energize, etc.

 

[2014highmiler]

Well, the window motor is fine.



The switch is fine.



There is power to the switch, but of course the BCM has to be told to energize the window motor, so somewhere there is a lack of communication.



It might be that the driver's switch is pooched, or perhaps the wires for the up/down function are pooched somewhere.



Not too sure I can go much further.



Would GM's computer spit out the answer if I took it to a dealer?

 

[2014highmiler]

Please see below. After reading this, do you feel that the rear passenger window switch requires permission from the BCM to operate, or does the BCM only come into play when the driver master switch is utilized to operate the rear window?



BODY BUILDER MANUAL FOR 2015 CHEVROLET SILVERADO/GMC SIERRA ELECTRICAL SECTION



Passenger, Left Rear and Right Rear Express Down Power Windows For the passenger, right rear and left rear doors, when their window switch is pressed in the down position, battery positive voltage is applied to their respective window motor control circuit and ground to the other window motor control circuit causing that window to open. When the individual window switch is pulled in the up position, voltage and ground is applied to the window motor in the opposite direction causing that window to close. The return path to ground is supplied through the inactive control circuit being normally grounded through the window switch. Each passenger and rear window switch communicates to the BCM by a serial data circuit. When the driver wishes to control the passenger, left rear or right rear window, the driver will use the appropriate switch on the driver window switch. When this switch is used, a serial data message is sent to the BCM requesting a window motor command, the BCM will then send a serial data message to the appropriate door window switch which will then command that window to move in the direction requested.