Central locking problem with passenger lock

[ghrays]

The central lock, double lock and unlock functions from the driver's side door lock work fine. The double lock function of the driver's side lock button also works, and locks all the doors, trunk and fuel filler door.

The trunk lock works and when locking with the key, all of the other doors and locks lock as they should (central locking).

The issue is with the passenger door. When using a key, you can lock or unlock that door lock only. The other door (drivers) does not lock or unlock from the passenger's door lock/key like it should. I took the passenger door lock out and it is in good condition and seems to function normally. The passenger door's microswitch also seems to work: I checked continuity and it bridges the brown (ground) and yellow/blue wires when the switch is depressed by the lock.

Since the passenger door responds to the central locking commands from the driver's side lock, I assume the passenger actuator motor is working. This implies there is an issue with the signal from the passenger door microswitch to the central locking control unit, or the CLCU itself is faulty;.

Has anyone seen this behavior before? I have the ETM for 1990 coupe 325i and the section on the central locking is daunting to say the least.

[reelizmpro]

Next thing to do is unplug the door jamb connector and clean it out or even replace bad pins. The pins get corroded over the years.

[ghrays]

Next thing to do is unplug the door jamb connector and clean it out or even replace bad pins. The pins get corroded over the years.

Thank you, I did this and the C404 connector was badly corroded. After cleaning the pins, the central locking now works from the passenger keyed lock. I wanted to replace the C404 and C405 connectors and their pin/sockets but most of the parts are now NLA.