Door locks unlock but do not lock. on 2003 GMC Yukon

I have a 2003 GMC Yukon. Both rear doors and tailgate doors unlock but do not lock. This happens with FOB, door lock switch on driver door or when putting the vehicle in drive. I replaced one actuator and there was no change. I refuse to pay dealership to fix. Can anybody help me out? Thanks.

by in Allison Park, PA on January 19, 2013
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2 answers 1 comment
ANSWER by , January 19, 2013
maybe you have an electrical issue with the door locks
COMMENT by , January 19, 2013
Thanks, can I easily troubleshoot that? I agree that it may be in the wiring somewhere.
ANSWER by , January 19, 2013
All the door locks communicate through the door module which is the complete assembly within the door. I hate to say it to you but this might be one of those times you want to take it to the dealer. Usually when you have something diagnosed at the dealer and have them do the repair they will waive the diagnostic fee. Be warned if it is a bad door module it can be caostly but you can't get it at aftermarket parts stores anyway. I'm not sure about rock auto or anywhere else.