Central Locking Strange Issue

[Kevinb]

Firstly, thanks to everyone who has helped me in the past.

 

Very odd issue with the central locking. I have been working on the rear left passenger door electrical connector this afternoon. I found 5 broken/breaking wires which I've reconnected for now (more permanent fix coming in the future). I ensured the connector was disconnected from the rest of the car before I started although didn't disconnect the battery (I know I know!). Upon finishing the job and finding the rear left window now works, I've found that the central locking has gone a bit funny.

Before I worked on the rear door, I did fix the front door's wiring rubber boot cover back into place as it had been disconnected at some point. The cables were all okay though.

 

If I operate the central locking from the front passenger's side, it works for both locking and unlocking (although it the unlocking sometimes took a few seconds to unlock the other doors).

If I operate the front driver's side lock, all locks initially operated in both unlocking and locking except the front passenger's door without any issue. However, later on this evening, I tested it again and found that if the car is locked, and then unlocked in quick succession, it won't unlock the other doors. If a few seconds goes by between the two processes, it works fine 

If I use the inside door locks, it mirrors the above although the passenger lock doesn't "feel" like it's part of the central locking system. I'm not sure why this is and may just be me being sensitive to the situation.

If I open and hold the key in place all windows operate in both lock and unlock, which it didn't do until this afternoon.

The boot gaiter, while a small disaster, has no broken cables in it.

 

Clearly, the central locking works and so I can't see it being the actual door lock(s). Initially, I was going to say I didn't think it was the central control unit either, but given the intermittent function if lock/unlock if operated quickly, I'm not so sure. I'm thinking it might be a wire but very carefully pulling on each cable in the front passenger door connector seems to indicate they are secure (ie not broken), or the central locking motor on the passenger's side being old and on the way out.

 

Anyone's ideas and suggestions would be gratefully appreciated before I end up having to take it to an auto-electrician...

 

Cheers everyone,

 

Kevin 

Edited August 3, 2015 by Kevinb

[gregers]

check check and recheck ALL wires in ALL gators in the doors including the 1 in the rear hatch.

[BrianH]

I think your diagnosis of the passenger side lock motor sounds likly. It could be a broken wire in that door if you haven't already checked, but the lock motor itself sounds suspect to me (as if your turning the key or moving the handle the motor isn't being used)

[Kevinb]

Gregers - I really have checked all the cabling as this one of the first things I thought of. I then rechecked them. The front door cables - both sides - really are in good shape. For a T reg, I was very surprised. The rear hatch cables were not in brilliant shape originally and had been "fixed" by a previous owner. I'm not bad at soldering though and so got a nice clean repair job. THey are still in good shape. Again, somewhat surprised but I won't complain!

 

BrianH - speaking entirely hypothetically here... Let's assume the lock motor has packed in. Would I be correct in saying that by turning the key the motor isn't needed, and therefore not engaged? Conversely, if the driver's door or rear hatch locks are used, the passenger door motor needs to engage? Apologies if it's basic 101 here, I just want to get my diagnosis process right!

 

Anything else you can think of? From what I've read, central locking gremlins are aplenty on these cars. One odd thing though, the central locking ECU is not under the passenger seat, which is as dry as a bone.

 

Cheers,

 

Kevin

[BrianH]

I believe that is the case yes. Early ones had it under the passenger seat where it learns how not to swim hence all the problems with them, they are elsewhere on later ones (later being about halfway though the mk1 life - not entirely sure where offhand but not under the seat).

 

Only way to tell for sure is to rule out one part or another - you've checked as much as your able to of the wiring (short of testing with a multimeter from end to end, which isn't the easiest of tasks) So i'd be replacing the lock motor if it was me. Only way to rule it out is to swap the electrical connectors over to a known good unit and see if the problem stops (this could be done without removing the current motor provided you operate the catch to the shut position with a screwdriver first)

 

The global window closing not working till you repaired the cables isn't a surpise - the boot wires being broken/shorting could be the cause of this anyway since it operates from that one as well.

 

Final thing - have you replaced the cables or just rejoined them? Rejoining them as they are won't last long!

Edited August 3, 2015 by BrianH

[Kevinb]

Brian,

 

Many apologies for not replying sooner.... Much to do around the house and a partner who gets her money's worth.....!

 

I did wonder about having a play with a replacement unit to test while leaving the other unit insitu. The very strange thing is that not long afterwards, it all started working again. How damn bizarre. 

 

I soldered the leads back together again and wrapped them in insulating tape. Not ideal, but good enough until I can resolder them (I didn't have any fluxite at the time so it wasn't the best job...) and make a more professional job of it.

 

Like I said very bizarre indeed. However, many thanks for your help.

[BrianH]

Its probably going to be one of those annoying problems that comes back intermittently, I had major issues with mine until i ended up giving in and investigating the rear hatch door which i suspected was the issue, That one by far was the worst, mainly as someone else had been there in the past though (silicon sealent, earth sleeving, terminal blocks and a right bloody mess was discovered).

 

I bodged the drivers one originally with a butt connector - when i came back to it to sort properly the wire had nearly snapped again! Soldering it new pieces of cable is definitely the way to go, as the soldered joints don't flex as easily.

[Kevinb]

BrianH,

 

I suspect you may be right. A local Auto Electrical workshop recommended a long term workaround for the rear hatch by soldering in about a foot of extra cable which could then be fed into the boot and/or main chassis. However, in this case there isn't anywhere for the soldered joints to go is there! More recently suggested simply replacing the door loom but I dread to think how much that would cost from Ford... The curious thing is that I've check all the door/hatch cables and they are all connected fine. It really is very odd, and without being "intrusive" - and possibly damaging perfectly good cables, I don't think the issue is with the cables, bucking the trend so to speak.

 

I was surprised to hear that the auto-electricians didn't recommend soldering the leads, insulating them, then taping them all up together into one large cable that would surely be stronger than the individual cables alone. I would have thought the leads would have fed back into the door void when the door was closed, but apparently not.

 

Very strange indeed.

[BrianH]

strength would be its downfall - it has to flex too much in the first place hence they break. Trailer cable is your best bet as thats designed to flex for the smaller cables, rest I'd do in single runs of the same size as the existing cable.

 

You should be able to make one end of your new run inside the car (near where the rear seatbelt goes into the pillar) and the other end inside the boot lid itself where neither section needs to move (make yourself some slack by undoing the cable restraints inside the rear hatch first then pull your joint back into the door, similar technique inside bring the end somewhere convenient and work on it then put it back, just make sure the joints aren't subject to bending when your done and it should be fine)

[BrianH]

oh and use heat shrink over the joints not tape - its a far neater job that way, and should last longer.