Central Locking??

[rightcar]

Hi.

I have a problem with my 2002 mondeo central locking and in the process I have to ask how it works.

I can hear the motors powering but they will not lock they just click, however, if I manually lock the doors and press unlock on the key fob they will unlock, try locking again and they click but do not lock.

i have covered the locks in WD40 but that has not helped. so it looks as though I am going to have to have a look at the electrical or mechanical side of things.

So the question, How does central locking work?? is there a master motor/ sensor or are there 5, 1 for each door including the tailgate.

if anyone has any idea on this problem then please feel free to help me out, this is driving me crazy. There is obviously not a signal problem because the motors make a noise, if I manually lock and press unlock they work but they will not lock, not with the key fob or by using the key...when using the key on the drivers door the drivers door only will lock though??

 

[Sceadwian]

30 seconds on Google returned a few people that have had issues with central locking/alarm systems that reference the bellow link.

Shooting from the hip I'd say it's a push/pull solenoid and there's a problem with one of the main relays that's causing a voltage drop that's pulling enough power to keep the solenoids from producing enough force to trigger it one way.

**broken link removed**

 

[rightcar]

Could a problematic relay cause this to be intermiitent?? Because this morning I went to the car and the locking worked 6 or 7 times before failing again.

Very peculiar. All help gratefully recieved.

 

[Boncuk]

I had the same problem with my Scorpio. The electronic starts locking but then gets a faulty 'door closed' signal from any door. After locking halfway the circuits unlocks again in that case.

Check both front door switches. They give erroneous information to the board computer even when moist.

I guess the logic used is TTL-logic. TTL-logic pulls itself up if not properly connected to ground.

Boncuk