I've got an 04 Sahara. Last December I noticed the driver side door lock wasn't locking when I use the key. It was fine when I used the lock on the inside door handle, just not the key on the outside. I finally sat down to figure it out last night and started taking everything apart to reach the lock mechanism. After some testing I found the mechanism itself worked fine, but the key still couldn't lock it 100% of the time. Sometimes it could barely get the thing to move, but not all the way. I started trying to troubleshoot the problem, isolating different parts of the lock to determine what exactly was the problem.
I took the passenger side door off too to cross check and see how the mechanism worked. I started by swapping the rods that connect the key cylinder to the mechanism. No effect. Then I took both driver side and passenger side cylinders out to look at them both and see if there was any difference. Before I headed inside to examine the cylinders, I sprayed a liberal amount of WD-40 on the mechanism. I looked at both mechanisms and determined there was no notable difference. They both turned the rod mount bracket the same amount. I decided to swap the brackets attached to the cylinders to see if there was any notable effect. When you do this, you have to also swap which side of the cylinder the bracket is on due to them being from different sides of the vehicle.
I installed the Passenger side cylinder with Driver side bracket back into the passenger side and tested for function. It worked. When I installed the DS cylinder with PS bracket back into the driver side and connected the rods, I tested for function, and it worked flawlessly. My buddy suggested it might have been due to the WD-40 freeing up the mechanism. Maybe it was too stiff for the cylinder to lock before. So I decided to swap the brackets back on the appropriate cylinder. When I did this and installed them back into their corresponding door, I tested for function again and found the driver side door still wouldn't lock after several attempts, the passenger door still works fine. This was interesting to me because the DS cylinder worked fine with the PS bracket, and the PS cylinder worked fine with the DS bracket. So this time I kept the bracket to the appropriate cylinder and swapped sides. Both doors worked.
So to sum up:
DS Cyl/DS Bracket on DS does not work, PS Cyl/PS Bracket on PS works;
DS Cyl/PS Bracket on DS works, PS Cyl/DS Bracket on PS works;
PS Cyl/PS Bracket on DS works, DS Cyl/DS Bracket on PS works.
Sorry for the long read, just thought this was weird and maybe helpful for someone with the same problem.
I took the passenger side door off too to cross check and see how the mechanism worked. I started by swapping the rods that connect the key cylinder to the mechanism. No effect. Then I took both driver side and passenger side cylinders out to look at them both and see if there was any difference. Before I headed inside to examine the cylinders, I sprayed a liberal amount of WD-40 on the mechanism. I looked at both mechanisms and determined there was no notable difference. They both turned the rod mount bracket the same amount. I decided to swap the brackets attached to the cylinders to see if there was any notable effect. When you do this, you have to also swap which side of the cylinder the bracket is on due to them being from different sides of the vehicle.
I installed the Passenger side cylinder with Driver side bracket back into the passenger side and tested for function. It worked. When I installed the DS cylinder with PS bracket back into the driver side and connected the rods, I tested for function, and it worked flawlessly. My buddy suggested it might have been due to the WD-40 freeing up the mechanism. Maybe it was too stiff for the cylinder to lock before. So I decided to swap the brackets back on the appropriate cylinder. When I did this and installed them back into their corresponding door, I tested for function again and found the driver side door still wouldn't lock after several attempts, the passenger door still works fine. This was interesting to me because the DS cylinder worked fine with the PS bracket, and the PS cylinder worked fine with the DS bracket. So this time I kept the bracket to the appropriate cylinder and swapped sides. Both doors worked.
So to sum up:
DS Cyl/DS Bracket on DS does not work, PS Cyl/PS Bracket on PS works;
DS Cyl/PS Bracket on DS works, PS Cyl/DS Bracket on PS works;
PS Cyl/PS Bracket on DS works, DS Cyl/DS Bracket on PS works.
Sorry for the long read, just thought this was weird and maybe helpful for someone with the same problem.
