I had an auto start installed in the truck back in 08 and the auto start also locks and unlocks the truck along with the original key lock. About 2 years ago it started "not" locking and unlocking the rear drivers side door. Sometimes it will and sometimes it wont depending on if I use the autostart to lock and unlock it. Ive tried all scenarios such as only locking it and unlocking it with the key only and vise versa with the autostart and same thing happens. two weeks of using either or, that back door just wont lock or unlock with either mechanism.

Any suggestions?

 

I had the same problem with mine. Turns out the wire bundle from the pillar to the door was worn down so bad that that some of the wires had literally come apart. took a couple hours soldering and reconnecting all the little wires back together so I had power windows locks and a speaker again.

 

Where exactly is the pillar?