I was driving home through a downpour yesterday so I put my lights on. I noticed that when I came to junctions, I needed some revs to keep the car charging. At first I thought slipping alternator belt or another failing alternator, but I had a feeling that the car was drawing more electrical power than it rightfully ought to be doing. I therefore turned off the headlamps but kept the side lights on. Still, there was a lot of power draw and the indicators didn’t seem to be getting enough voltage to run. It was at this point I exited the dual carriageway and switched all electrics off apart from the engine. A bit of switch flicking confirmed that the side lights were definitely pulling far too much power so I began to suspect a short circuit. I spent this evening tracing things through and found that a couple of feet of the rear loom in the boot by the spare wheel had severely melted. It might be hard to ascertain exactly where the fault started, but at the moment it looks like age related insulation failure. I plan to chop the melted section out and replace with new wire, and hopefully eventually replace with a new rear loom.
My trunk harness where it runs underneath the rear quarter was melted together in exactly the same way! Almost like there was a nasty solvent applied that softened and swelled the insulation over time
Glad you caught it when you did
This is most definitely a short circuit. Yours may well have been one too.
I’ve just come in from having a further look and I’m suspecting that the positive wire to one of the number plate lamps has chafed through on the bumper and caused a dead short. I’ve not removed the lamp yet, but at the moment it looks like that’s the source.
Can anyone tell me if the lamps are just nut and bolt, or into a captive or welded nut? It’s one of the nasty pattern rear bumpers, not a genuine one. I don’t want to undo the bolt at the lamp only to find the nut spins and I have to pull the entire bumper off. That’s not a job for tonight.
Mine were nut and bolt. pain in the ass. Just got finished rewiring the entire trunk area and re-sealing the bumper mounts with Strip-Calk.
Can the bulb be accessed without removing the whole lamp? What happens when you undo the two screws? Does that just remove the bulb cover or the entire lamp assembly?
If you remove the pair of screws, the chrome cover snd glass can be removed, which gives access to the bulb..Tony
yup two sets of screws: one for the cover and the other for the base
Source of the short circuit found. It was indeed the number plate lamp. I haven’t removed it yet to see exactly where it failed, but it might be internal to the lamp. Being an early car, none of these circuits have any fuse protection at all. Just something to be aware of!
I’ll cut out the burnt bits and patch up the wiring for now to get the car running, and order a couple of new lights. Hopefully I’ll get to do a better job of replacing the wiring over the winter when the car is garaged.
