i have a 2005 sierra crew cab. im haveing problems with the rear door locks. they will lock with the switch and the keyless entry but i have to unlock ...

i have a 2005 sierra crew cab. im haveing problems with the rear door locks. they will lock with the switch and the keyless entry but i have to unlock them manualy, they will not unlock with the switch or the keyless entry. has anyone ever heard of this problem and know how to fix it?

Yes, this is most likely the unlock relay. It's located in the interior fuse panel, on the left side of the dash. Swap the lock and the unlock relays and try it. If it will do the opposite action (unlocking) after you swap them, you've found your culprit. It should only cost a few dollars. Make sure to use dielectric grease on the contacts when replacing.

If the relay isn't the issue, you might have a bad BCM (which controls those relays) or there could be a wiring issue between the BCM and relays or between the relay and the lock actuators. It really sounds like a relay though. Let me know how it goes.