Anybody have a good understanding of the electrical door lock system in an 89 XJ40?
I (personally) installed new front door handles a couple of years ago when the passenger door handle started feeling like it might be mechanically broken.
My electric door locks started misbehaving a few months back, going "out of sync" occasionally where some doors would lock/unlock when the key is turned and some wouldn't, etc. Recently the driver door lock stopped unlocking the door when the key was turned in the lock; I had to use the passenger door keylock to unlock the doors, and to lock the doors I had to either reach across and push the passenger side lock knob down or walk around to use the key on the passenger side. The lock panic switch on the dash stopped working at some point, but I rarely used it so I'm not sure when.
I had the car in the shop this week for other work and I asked them to look at the driver side lock, since it's a pain to have to walk around to the passenger side to unlock the door... they disassembled the door and said a worn lock lever was causing the problem, and by using some parts I had left over from my prior handle replacement, they were able to repair that lock so that the drivers door lock can now be used to unlock the car (unlocks all 4 doors). Apparently I must have used the old lever when I replaced the drivers door handle.
BUT, now when the driver door is locked with the key, the rest of the doors remain unlocked, so I still have to either stretch across the car to push the lock knob down or walk around and use the passenger door to lock the rest of the car doors. So, the shop only fixed a part of my problem. The switch on the dash still will not lock or unlock the doors. I can hear a faint click in the forward area of the passenger door when I attempt to lock the doors using the driver's side lock.
Any ideas as to what the problem is? Is there a relay or solenoid in the front passenger door that is failing (ie, a relay actuated by the driver side lock but not by the passenger side lock)? Is the control for all 4 door locks located in the front passenger door? Or what? ...ie, how are the door locks supposed to work?