530i Door Lock/Keyless Entry faults
The car is a 530i with the build date of 10/1995. The alarm is OEM with the squarish 3 button remote like this:
So, since I've had the car the door locks never worked quite right. If you locked or unlocked the car using the remote, the passenger rear door lock would not work. Pressing the driver door lock peg down while in the car to use the central locking would yield no response from this lock either. Unlocking the car using the key in the driver's door did nothing as well. I assumed the passenger rear lock actuator was dead.
Out of nowhere this all changed. One morning I went out to unlock the car with the remote. The driver's door did not unlock but the passenger rear door did unlock! I manually unlocked the driver's door using the key and got in. I found that using the remote will not unlock the driver's door but will unlock all other doors. Pressing the driver's door lock peg down to use central locking will work on all doors. Manually unlocking the car using the key in the driver's door will unlock all doors as well.
Any ideas? I searched to no avail. Is the alarm box bad?