So I'm new here, and forgive me for reposting about something that has been discussed. I didn't really see my car's exact symptoms, so I thought I'd start a new thread. Please help!

Anyway, just bought an 01 XJ8 the other day. Gorgeous car, 77k mis. Has some strange quirks, one of which is that my locks are definitely not working like they should be. I can get all the doors to lock and unlock by using the key in the driver door. When I'm inside, if the doors are locked and I press the lock button on the dash, the doors will unlock. When I press it again though, all I get is a clicking sound. from the doors According to the handbook, one should also be able to lock and unlock all the doors by raising or lowering the lock on either the driver or passenger front doors. This doesn't happen either. I've checked the fuses and unplugged and replugged in the lock relay to no results. I'd really like to be able to lock the doors when I'm driving without having to roll down the window and lock the doors with the key while I'm inside! Any insights would be hugely appreciated!!

 

Chasing electrical problems can be fun.

The first thing I would do is replace the lock relay. Look online to find the part. Much cheaper than at the dealer. Relays can be quirky when they are going bad. A little bit of carbon build up on one side of the conductor and things don't work.

While you are at it check the switch. Make sure you have continutity when the switch is pressed and that you have an open when you release the button.

I don't think the problem is in the doors since neither door will cause the locks to actuate, so what ever the problem is it is common to both side of the lock circuit.

Good luck.