4x4kiwi

Came back to parked car to find the locks continually cycling lock - unlock. Thought it was caused by a recently fitted alarm which interfaces with the central locking so removed the power feed to the alarm. A bit later while driving it started cycling again so remembering that the alarm only puts a ground onto the lock motors decided to completely disconnect the alarm thus removing these (two separate) ground feeds. Bugger me later it started cycling again. This time I thought to remove the fuse that supplies the power to the central locking motors so this stopped it. This all happenned while out in the middle of no where following the WRC Rally with no tools so a bit stressful as I thought it would burn out the motors if left to cycle. I now believe it is nothing to do with the alarm but as it is two different lines for lock and unlock dont so much suspect a chaffed wire shorting to earth. During a search on here I came across the following in a reply to someone elses different problem from member Iansoutham.

"It could still be the CDL module itself, but most likely it is the motor or latch. Wiring issues normally cause random "cycling" of the locks. If a master motor should lose its earth connection, then it would become a slave unit. This would cause the system to always "cycle" as these motors cannot operate on a single master circuit as they always require the second master to act as a confirmation."

This will be my first thing to try during fault finding but can someone confirm this is true and also according to the wiring diagrams all the lock motors just seem to be wired together without any sort of module or relay unit (I think the older systems had something) can someone confirm this also or shed light on what and where the CDL module mentioned in this previous post hides in a 1990 4x4 Cos.
Sorry for the long post
Thanks David

iansoutham

Hi, a 1990 Cosworth will not have a CDL module, it is a direct-wire system. I would check the wiring that goes between the door and the pillar on all 4 doors first with this. You need to try pulling the wires gently apart along their length where they go through the rubber boot. If the wire "stretches", then the break is at that point. If the yellow and white wires touch each other or earth, or the brown wire on the front motors breaks, it can cause this problem. I normally use a voltmeter set to ohms and do a circuit test on each individual wire.

I have also found that sometimes they can cycle once warm only. My other half has a 2000e which has the early locking system (June 1989) and when sat in the sun for hours in summer, will cycle once activated. I have narrowed it down to a possible latch internal fault on one of the front doors.

dojj

iTrader: (3)

if it's a 90 spec car then the cycling can be the motors themselves or, in one case, the actual lock that had failed

it will be either of the front doors anyway so simply undo the passenger side door card, unplug it and see if it stops

4x4kiwi

Thanks for the replies. I may need to wait until next weekend before I will get time to look into it again. The trouble is it seemed to be a bit intermittent sometimes stopping by itself before I did anything. I will run with the fuse out until then. David