Back door driver side lock only works manually

First off, let me say this site is great and I have been able to find answers to all of my prior problems just by doing some searches. Unfortunately, this isn't one of them.

I have a 2001 GT and this morning I pressed the keyless remote twice, but the driver side back door didn't unlock (all other doors did). I tried using the switch on the driver's door that unlocks all of the doors and it still did not open. I manually unlocked it, closed the door, and tried the keyless remote to lock all doors. It didn't lock. Same when I put it into park and turn the ignition off, it doesn't unlock. I'm guessing it's a wiring problem, but I'm not sure what all can go wrong on electric locks to cause this.

Any ideas what would cause one lock to not work while all the others do?

The best thing to do is pull off the door panel and inspect the wiring especially to the door lock actuator. You can check at the electrical connector to see if the 12v is getting to the actuator from the body control module (BCM) when pressing the RKE. Also the ground should be checked to make sure its good.

Thanks for the reply, bnaylor. Assuming it isn't the wiring (haven't gotten to check since I'm at work), do the actuators themselves go out on these much or is that not a common problem?

It's not a common problem but actuators do go bad. There are two wires on the electrical connector plug to the actuator of concern. Pin A (tan wire) is unlock and Pin B (gray wire) is lock. You can check the voltage at either pin. If voltage is present then the actuator is bad. Good luck!

You're welcome.