Door sensor / alarm problem

[Dan P]

Eve, my Mk2 Focus, has developed a little problem over the last couple of weeks.

On a few occasions whilst driving I've had a warning that the rear passenger door is open which has now developed into the alarm going off occasionally whilst the car is parked up.

I'm guessing that there's a problem with whatever it is that detects that the door is closed. Is there some kind of sensor in the lock mechanism?

Any suggestions on how to resolve this would be appreciated - (i) what can I do to fix the problem? (ii) what components may need replacing? (iii) can I bypass it?

[Dan P]

After the alarm went off three times last night I then thought about locking the car with the key rather than with the remote. Am I right in thinking that this does not enable the alarm?

[Dan P]

Bump. Can anyone help?

[Dan P]

Traced the fault to some shoddy workmanship (by me) when I replaced the door last year! I had also worked out a plan to bypass the circuit, but thankfully didn't require it. Full details here on my build thread.