central locking problem

I noticed that my central locking on my 1995 Trident was only locking the front passenger door and not the driver's door. My Dad took the door trim off and removed the actuator and tested it with a 12 volt supply. The actuator retracted so he assumed that the problem is with the wiring. Obviously, the fuse is OK as one door locks and unlocks correctly. There was no obvious problem with the wiring in the door. Any suggestions where to look next?

My Topaz has the same fault, but haven't had time to check it out.

In a 1995 vehicle the cabling from door to vehicle will have been bent many times as the door is opened and closed. There is a limit to how much bending a cable can stand and it may surface in the symptom you describe.         Keith

Thanks for your reply. The other door has a similar problem now! Problem is broken wires in door shut area as predicted. Presumably it is feasible to make a short link loom to overcome the problem. What wiring gauge? Has anyone done this on their van?

That's got to be a record - a year from post to follow up.

caroline70 wrote:What wiring gauge?

Simply use the same size wire as is there already. Car wiring is sold these days expressed in mm squared, so all you need to do is measure the core diameter of the existing wire, and use your rusty school maths to calculate the area [pi * (diameter/2)squared].

The easiest way (IMO) to do a splice like that is to buy heatshrink to go over the soldered joints, and to offset the splices in adjacent wires so they don't all sit in the same place. This makes the overall joint smaller and makes it easier to pull through the rubber gaiter at the door hinge.

-mojo- wrote:

caroline70 wrote:What wiring gauge?

Simply use the same size wire as is there already. Car wiring is sold these days expressed in mm squared, so all you need to do is measure the core diameter of the existing wire, and use your rusty school maths to calculate the area [pi * (diameter/2)squared].

The easiest way (IMO) to do a splice like that is to buy heatshrink to go over the soldered joints, and to offset the splices in adjacent wires so they don't all sit in the same place. This makes the overall joint smaller and makes it easier to pull through the rubber gaiter at the door hinge.

In areas subject to repeated bending, such as the loom to the door, it's highly desirable to keep the soldered splice joint completely away from the hinge area if at all possible. For example you could let in a longer section of wire and splice it into the loom at both ends of the failure point, then shove one spliced joint into the A-post at one end of the repair, and one into the door at the other.

Mojo's advice to offset multiple joints is sound, however any joints in the area subject to bending may cause greater stress to go onto other wires and/or result in bending stress being applied to the repair joints themselves, which is clearly not good practice.

This is a problem which VW Group vehicles still suffer: I'm aware that the Seat Leon 1P1 types is particularly susceptible to door loom failure.

Bartfarst

Agreed - I should have made it clearer that I would expect to splice in new lengths so that the new wire passes right through the gaiter, replacing all of the previous wires that have been subject to constant flexing.

No doubt VW would say that it makes a significant weight saving, but they have cut back their wire sizes too much IMO - for example the headlight wires on the T5 are too thin for my liking, and although they are not subject to flexing, it does result in a significant voltage drop.