so i can unlock all my doors w/ the remote or the switch on the dirvers door but, the rear doors wont lock. befor i start taking the truck apart any of u know of where to start digging into the truck to fix this. im sick of parkign my truck and having to manualy lock the back doors each time.

oddly the alarm will arm jsut fine but still not lock the rear doors. i noticed this a week ago when i walked up and opend the rear door jsut to have the alarm go off...... ug. goodthing no slime ball figured this out befor i found it.

thanks

i'd say check the fuses under the hood. i had a problem w/ my windows not wanting to roll up on the pass side. checked the fuses and had 1 blown. now they are fine. oh and i figured that out after i took the damn door panel off. learn from my mistake :)

any luck yet?

checked all the fuese, they were fine, also checked the plugs where the doors plug into the cab as i had removed the doors to paint the truck all were also fine. its raining today so ill mess with it more over the weekend. im kind of stumped.

thanks

Check the drivers side front door wires. I removed mine and pinch the wires when I put it back on. Mine did the same thing.

i have taken all 4 doors apart trying to find a issue and have found it all to be just dandy.

iv noticed the rear door locks work some times then not others.... im totally lost. maybe my drivers door lock switch could be the issue? i image that the drivers door lock controls all the doors even when the remote is used. ug..... so annoying to have to manly lock 2 freaking doors every time i park the truck.

I just had my truck in last week for similar problem. drivers door wouldnt lock or unlock with remote or switch on door. Dealer replaced motor (selonoid, what ever you call it), they said they have had a few trucks come through lately with same problem. Could be the case with yours.

Swap door lock relays and see what happens...

Mine does the same thing. I can usually get it to work by hitting the lock button then the unlock until it works.

Mine does the same thing. I can usually get it to work by hitting the lock button then the unlock until it works.


would that indicate that the switch is just full of gunk and needs to be simply cleaned out?...... i knocked a lot of dust and such out of mine the last time i had removed mine from the door panel. maybe these switches can be taken apart and all the contacts cleaned up? im not sure how the switch being full of gunk would make the keyless entry not work but hay im up for anything.

ill be doing work on the truck in preparation for winter this weekend, so ill try swapping teh relays and also the wires and switches in the drivers door again.

thanks for the tips guys

Had this problem start about 3 weeks ago. Rear doors unlock just fine, won't lock. Switched relays, no luck. Went ahead and ordered new relays from an online company, just tried them. no joy. I can hear what sounds like the solenoids working in the doors, they just won't lock. I'm also looking for anything to solve the problem.

Had this problem start about 3 weeks ago. Rear doors unlock just fine, won't lock. Switched relays, no luck. Went ahead and ordered new relays from an online company, just tried them. no joy. I can hear what sounds like the solenoids working in the doors, they just won't lock. I'm also looking for anything to solve the problem.

i actually stood back by the rear doors as someone else hit the lock button and if mine don't lock i don't here any sounds at all. but that dosnt mean much. let me know what u end up finding out is wrong with ur truck.

I know it's an old thread, but has anyone found the answer to this problem? I just noticed the other day that my truck is doing the exact same thing as Wellfooled's.

My truck did the exact same thing with the rear locks for about 2 months then cleared up. Never did it again. Never found an obvious problem. I did notice my heated seats failed around the same time, but the still dont work. Havent fooled with it. May be related, somthing like drivers door module or BCM. Only the GM gods know:p:

There are 2 relays in the fuse panel at the drivers feet. One for unlock and one for lock. They only work the back doors. They work together so get a new relay and switch one out but dont get rid of it till you make sure that it fixed the problem. If the problem isnt fixed switch the other relay instead and that should fix your problem. I had the same issue and first changed the lock relay but still had the problem. Then I changed the unlock relay and havent had any issues in the past 6 months.

awesome!!!! thanks for the help.... I'll be trying this this weekend.

There are 2 relays in the fuse panel at the drivers feet. One for unlock and one for lock. They only work the back doors. They work together so get a new relay and switch one out but dont get rid of it till you make sure that it fixed the problem. If the problem isnt fixed switch the other relay instead and that should fix your problem. I had the same issue and first changed the lock relay but still had the problem. Then I changed the unlock relay and havent had any issues in the past 6 months.

Do you have the part number for this relay and what did you pay for it? TY

I went to the dealer and paid 30ish for one. Sorry dont have the part number. I just pulled one out and handed it to the parts guy.

well, out of the blue my rear doors started working ok, then now there not again. so back on the hunt. i think my problem is either the switch or relay. time to get testing.

My 03 did the exact same thing a couple years ago, some times they would unlock and work for months and then all the sudden nothing, then they would work again. I swaped the front door lock relay with the back door relay and the problemed moved from back to the front proving to me that it was the relay. I took the relay to the dealer (don't know the part # either, but it's painted on it, paid 25 dollars and it's worked since. the relays are behind the fuse panel on the side of the dash, drivers side. Good luck!

Add me to the list, an 03 with exactly the same thing! Rear doors wont lock, but they do unlock. Either by using the switches on the front doors or by using the remote. I'll report back with the outcome. Sounds like the relays are the first place to start...


ETA- Yep it was the relay. I switched them around and I got the rear doors to lock. When I switched them back I don't know if I then blew the good relay or if I got them confused. I could not get the doors to unlock! So anyway I found at least one place online that sells the relay. $11 e@. http://estore.websitepros.com/2091945/Detail.bok?no=219

watersniper.! good score on the relay prices!....

anyone ever find a part # of the relay's that work the front and rear door locks?

i finally had some time so i started looking into this problem fairly in depth.

1st. i removed both relays and opened them up (cover simply snaps off) both were fairly clean and didn't show any sign of a issue.

2nd. i took turns swapping the relays back and forth. both worked in either slot just as they should.

3rd. i took out the drivers door switch panel and 100% disassembled it. it had a lot of dust in it but didn't look as if there was anything out of place or damaged.

4th. i checked evey single fuse in the fuse block (u never know maybe it would be a simple fix) all were fine.

5th. i checked the door plugs going between the body and each door. all were properly plugged in and making a good connection.

after all this i am 100% lost as my rear doors do not want to lock at all. i have noticed that in really hot weather they don't unlock or lock.

does anyone have a pdf file showing the centrual locking electrical system? i figure something where ever power is sent to the rear doors must be the problem. i thought that maybe the door locks were all hooked to the drivers door switch panel but with the drivers door switch removed i still get power to the passenger front door so i guess there is a different location all the doors are tied into.

next i plan to pull the fuse box out of the dash and hope to find the wires going to the rear doors so i can track them from that point backward to where ever they on the way to the doors.

i am quiet amazed how overly complicated the locking system is in this truck. some of the German cars i work on a actually easier to deal with. ahha.....

i finally had some time so i started looking into this problem fairly in depth.

1st. i removed both relays and opened them up (cover simply snaps off) both were fairly clean and didn't show any sign of a issue.

2nd. i took turns swapping the relays back and forth. both worked in either slot just as they should.

3rd. i took out the drivers door switch panel and 100% disassembled it. it had a lot of dust in it but didn't look as if there was anything out of place or damaged.

4th. i checked evey single fuse in the fuse block (u never know maybe it would be a simple fix) all were fine.

5th. i checked the door plugs going between the body and each door. all were properly plugged in and making a good connection.

after all this i am 100% lost as my rear doors do not want to lock at all. i have noticed that in really hot weather they don't unlock or lock.

does anyone have a pdf file showing the centrual locking electrical system? i figure something where ever power is sent to the rear doors must be the problem. i thought that maybe the door locks were all hooked to the drivers door switch panel but with the drivers door switch removed i still get power to the passenger front door so i guess there is a different location all the doors are tied into.

next i plan to pull the fuse box out of the dash and hope to find the wires going to the rear doors so i can track them from that point backward to where ever they on the way to the doors.

i am quiet amazed how overly complicated the locking system is in this truck. some of the German cars i work on a actually easier to deal with. ahha.....

Check the fuse behind the panel on the side of the dash on the drivers side. I did almost everything you did then started checking fuses there and found one that was blown. Replaced it and wa' la I had locking doors again!

took every fuse out again today both under the hood and at the dash. no luck.

i also removed the plug from the in dash fuse box for the drivers door and checked each wire for connection from the plug at the fuse box to the other sides of each wire in the drivers door. all were fine.

im totally stumped. guess i own a 4dr truck w/ 2dr power locks haah.....

time to get my hand on some wiring diagrams. at this time im blindly checking wires from where ever i can get to the ends of them, i really dont have a idea what is what. i had been thinking it would be obvious when i found a problem, but that just isnt the case.

Just making sure you checked the right fuse box. The one I'm talking about is on the Side of the dash board on the drivers side. Not the one under the dash. Hope you figure it out. It sucks everytime you lock the doors you have to reach back to get the rear doors! Good Luck!!