Sorry to bring this up in the electronics section, but I've gotten little help elsewhere.

My C/C rear doors lock at 15 mph, as set on my DIC. They will also LOCK with the door button, as well as the key fob. However, NOTHING will unlock them, except my left hand reaching back between the seat and the door! I've checked my DIC, my owner's manual as well as the child safety lock switch in the door. Nothing APPEARS to be wrong, but let me tell ya, having to reach back and manually unlock EVERY time I need to open the back door is a real pain!!! :rant:

PLEASE HELP!!!!

In the fuse panel on the drivers side of the dash there are two grey? relays side by side. Try switching them. If after you switch them you doors unlock but don't lock then you know it is a bad relay. That would be my guess.

Thank you sir, I'll go try that RIGHT NOW!!!!

Max, YOU RULE!!!!!

I switched the two relays, and suddenly the back doors will NOT lock!!! I found it strange that it only affected the rears, and that each relay position on the fuse panel says "lock" or "unlock". I would have thought that all four would be affected, but apparently not...

THANKS A MILLION!!!!!

MP does rule when it comes to electrical stuff!!! :ro)

The relays only control the rear doors, that is why I suspected that first. Glad it works and a simple fix to top it off. I would be interested to see how long and how much it would cost to get your dealer to diagnose and fix that problem.

Welllllllll...............I thought this was solved, but its not. After flip-flopping the two relays, I "determined" that it was that rear relay. Today, I bought a new relay at the local parts store, and installed it. It worked ONE TIME, then stopped working. I think I burned a $20.00 relay up right there.....

Strangely, the "front" relay doesn't seem to "burn out". Now we're gonna test the "experts" and see what my issue is. BTW--my truck is not modified at all, I haven't butched into the harness anywhere for anything.

The front door locks are done in the doors with the door modules. The rear door locks are really very simple.

Are you sure you got the right relay?

What happened when you swapped relays? Did the doors not LOCK?

If you have a bad lock motor or a shorted wire it could cause this but it shouldn't burn out a relay. I wish you were closer, it would be a pretty easy thing to diagnose.

I'll check it again, but when I swapped the two OEM relays it made the rear doors UNLOCK, and I couldn't get them to lock. THus, an instant "reversal" of the original problem. What I did today was get an apparent match to the original relay that wouldn't lock. All of the numbers and locations matched the OEM relay, and I'm pretty sure it was the same. The parts counter guy seemed certain, and said he'd sold one recently.... He seemed more sure of things than I did. Its getting dark, and I'm not gonna mess with it again tonight, but I'll check it again tomorrow. If you wanna drive down and tweak it, I'll buy you dinner..............but won't touch you're fuel tab!!!!

Well, here's a weird one to add to the dilemma. If I remove BOTH relays, the front doors still work!!! Now how the hell does that happen?? I'm sensing a short circuit somewhere.... Any clue where to start my quest?

THat is normal. In a regular cab or an extended cab they don't have those relays. The relays are ONLY for the back doors.

OH!!! I thought it was a front and rear deal. So, what are your recommendations at this point?? Take it to the dealer?

Well, if you swap relays and the swapped relay that allowed the doors to lock previously, does not burn out in the unlock position, then I would think there was a problem with the new relay.

If there is a dead short, I believe a fuse should/would blow isntead.

andrew fessler has it right.

Okay, now its just getting plain weird. Today, I went out and flopped the relays AGAIN. Now, it seems to work correctly. 100% locking and un-locking. What gives???

I would be interested to see how long and how much it would cost to get your dealer to diagnose and fix that problem.

Free under warranty, but then again I sat there for 3 FREAKING HOURS waiting for them to fix 1 fuse and the relay, which had been removed by my friend when hardwiring the radar detector.
So 3 hours and shop rate of $70/hr = $210
$10 lunch/donut fee per person x 5 = $50
So roughly $260... Gotta love the forums and great help foun here!!!

That is EXACTLY why I came here first. I figured some of these guys or the techs that frequent this site could diagnose it pretty easily. I gotta say, I'm SHOCKED that its working (at the moment) and all I've done at this point was rearrange the relays a few time and tried to wear out the PDL switches!!!

Must have just been dirty contacts?