So I've recently bought a mk1 2.0 zetec focus. I've noticed that the front passenger door doesn't lock via central locking, but when I lock the car with the key in that door, it locks all the doors. The drivers doesn't. Its recently been trying to lock while driving but only if that door is unlocked. While that door isn't locked that's when it will attempt if the car is on or not. Ive changed the fuse. I believe this has started to happen when I put my subwoofer in. I've checked all the cables for the sub and all is fine with that. Also changed the 2 fuses for that as well. I'm 1. Curious why the passenger door doesn't lock with central locking on the key or via drivers door and why it attempts to lock the car while the passenger door is unlocked. Ps. When it attempts to lock and is unable to because the passenger door is unlocked the rear passenger side door ticks. While it is ticking if you were to lock the passenger door it will only lock that door. As if the central locking is disabled... Any suggestions on either a cure or reason why this is happening?

21 hours ago, Fraser214 said:

Curious why the passenger door doesn't lock with central locking on the key or via drivers door and why it attempts to lock the car while the passenger door is unlocked.

Hi, I am no great expert on this, but I would say:

Faulty limit switch on the locking latch in the pass. door lock. And / or faulty locking motor.

So the pass. door locks manually, and sends the signal to repeat this action on all other doors. But it ignores the electrical commands to lock / unlock, that are sent to it.

If this door is giving the wrong status about the state of its latch, then that may cause the BCM (main control module) to re-issue the lock command at times.

Also check the door ajar switch, ie the dash warning light & interior light behave as expected.

I think the latch mechanism may have to be removed for test / repair / replacement.

Thank you for your response. The dash lights don't come on and the door closes and opens fine. For some reason it doesn't respond to the button on the key, doesn't even attempt. The other doors will try to lock but that one doesn't move. I believe the reason why the doors try to lock while I'm driving is that I've disconnected the battery recently and its a security feature to lock the car when reattached. But where it hasn't been able to successfully lock that could be why it's repeating? Right? If it pass how would I get to it and where is it?

3 hours ago, Fraser214 said:

I believe the reason why the doors try to lock while I'm driving is that I've disconnected the battery recently and its a security feature to lock the car when reattached. But where it hasn't been able to successfully lock that could be why it's repeating? Right? If it pass how would I get to it and where is it

In many cars it is an option to have the doors self-lock above a certain speed. If it did not do this before, it may have gone into that mode after battery disconnect. Then if the BCM is not getting the correct signal, it may well keep trying.

I have just noticed the sub-woofer bit. Perhaps a connector has been dislodged. The locking is controlled by the BCM (aka GEM), part of the passenger fuse box, and will go through one of the connectors to that unit. Have a good look at the connectors in there, check they are clean & properly engaged. In the mk2 Focus, there are also some big connectors behind the trim panel just in front of the passenger door. These wires may go through one of those.

If there are no obvious bad connections, it will be best to take the door panel off, and test the unit at the lock, inside the door. Haynes describes door panel removal. I have only Mk2 Haynes. But basically the bezel under the door interior release handle has to be prised out, starting from the front edge. The cover under the door grab handle is levered out, then the two bolts under it are removed. Unplug any connectors as needed. Then with a forked tool or a pair of screwdrivers, locate the clips around the edge of the door, and lever between the door panel & a collar on the clip to release them.

This may give access to the electrical connector to the latch. However, removal of the latch is a rather lengthy, but not too difficult, process, involving dismantling most of the door. Will need a Haynes or other guide. Also the pin configuration of the connectors should be in the Haynes, I have not been able to locate a downloadable Mk1 wiring diagram. The Mk2 diagram I have will be similar, but pin numbers may not be right.

You are a great help, when I worked my sub it only used 4 main cables, power went straight to the +battery, the ground/earth was the same earth in the boot the battery shares, and the remote and audio are linked straight to the head unit. The lock wasn t working before I put the subwoofer in place which leaves me to suspect the lock or wiring issue for the door. Could it be possible that there may be a loose cable? Does the central lock in each door have its own earth? I do apologize for the lack of information I know about this.

3 hours ago, Fraser214 said:

Does the central lock in each door have its own earth?

On the Mk2, there are separate earths, on the left & right "front rocker panel" whatever that is. I think it is part of the main car bodywork, near the door. Almost certainly the Mk1 will be similar. One wire carries all the lock status and operating switch earths from each door. So that is a possible.

 

I will have a little look around tonight and keep you updated.