Central locking - mk 1

[Rebelbloke]

Hey all, bit of a strange issue with my central locking. Just wondering if anyone's come across anything similar.

Occasionally when I use the remote central locking, the car will lock but then the passenger door will unlock itself immediately after?! The alarm remains armed but the door unlocks itself. When I bought the car, the passenger side central locking was not working so I replaced the motor. It has worked fine until recently.

Any ideas?

Cheers.