driver's door doesn't auto-unlock on '02 2500HD

Wow, it's been a while since I've been on this forum! That's how dependable our '02 Sierra 2500HD has been! The truck has been great. We usually use it to drag our open trailer around with our dedicated autocross car on it. Other than that, and occasional big item move, it stays in our shop.

We were at a local autocross event yesterday, and I hopped in it to pull our roll-back trailer up after loading the car. When I finished that step, and then turned the truck off to get out and tie the car down, I noticed that the driver's door didn't unlock automatically. I tried the unlock button on the door, and still nothing. The key fob, the button on the door, and putting the truck in gear will all cause ALL of the doors to lock, but any attempt to get the driver's side door to unlock electrically, fails. I can manually-move the lock mechanism from the inside, or use the key on the outside but while it will automatically lock, no dice on the unlock.

I haven't done much digging yet, but wanted to check here to see if it's a common issue, or if anyone has any idea where my failure might be. The power windows work fine, and the lock/unlock switch on the door will successfully unlock the passenger's lock, but not the driver's.

Thoughts? Thanks!

Fixed!

For now, at least. Contrary to my belief, the Sierra has a separate relay for driver's door, and a separate loop for lock, and unlock. I located that relay on the left side in-cab fuse panel. Since it's the same as the passenger side relay, I figured I could at least swap the relays and see if the problem moved. Before doing that, though, I unplugged the current relay, and reseated it. Problem solved.

I'll probably get a spare, just in case this one completely quits, but it was certainly easy to get to and test. I'll post a picture of the offending part, if I can get my mail server to get off it's weekend break!

Just for completeness, here's the picture of the offending relay. It's in the lower left corner of the driver's side fuse panel.

http://media.fotki.com/1_p,rtrdqbwbb...krelays-vi.jpg

Thanks for the follow-up!