Unlock back door

SOURCE: 2004 tahoe

make sure than you have not split any fluids on the passenger front door most of the times is where the module to control the windows and doors is located, try by unpluging the batterie and the after a minute plug it back and see what happend but if any of your ft doors have been split with liquid or rain has gone inside then most likelly the module got moisture and not working

SOURCE: 2006 gmc yukon back door/hatch won't unlock

Check battery voltage. if above 13.7 volts move to rear lock actuator and measure battery voltage at actuator if above 13.6
replace actuator if below specs. check grounds and alternator out put as follows, alternator output 13.7 to 14.25 volts. key off battery volts should be 12.90 + - 3/10 of a volt and about the same voltage at the actuator. let me know. kindest regards Bill

SOURCE: Yukon xl rear door won't unlock and there is no manual lock.

I fixed mine by using fine steel wool to clean the brass contacts located at the right upper door frame on the right door as viewed from the rear of the vechicle.

SOURCE: 1999 gmc suburban, door lock won't unlock

You need your door lock actuator's replaced because they are sticking.

SOURCE: The cargo door and glass is locked, and the actuator will not unlock.

how do you removed the interior cover? for the rear door actuator?