Jaguar Repair: central locking, permanent magnet motors, door locks

Question
1987 xj6 central locking.... The front passenger door locks with all other doors but it doesn't unlock with the rest.  Any ideas?

Answer
Hi Bob,
The 87 has motorized door locks. The motors are permanent magnet motors, meaning they reverse direction when the polarity is reversed. The door lock switch just reverses polarity to all of the motors. The fact that the other locks work, proves that the switch and the power supply is doing it's job. The fact that the passenger door locks ok, proves the two wires going to that motor are connected and working. This means that the passenger motor has a mechanical problem unlocking the lock. You should remove the door panel and with a light and a mirror watch the door lock try to operate. If it is not evident what went wrong, disconnect the link and try to operate the motor with no load. Then try it with a small amount of load by hand. If it works ok check to see if you can easily by hand lock and unlock with the link.

Let me know how it comes out.

Howard