Head lamp grounding wire.

[Ceejay73]

Hello chaps,
wondering if any of you can help. I finally have the front back on my car and have discovered a grounding fault in the offside front lighting circuit. I have done all my checks and it is definitely the ground wire in the main loom to the multi plug. I can obviously work around this by just throwing an additional ground at it but the question is have any of you ever stripped back this section of loom and do you KNOW where, in the loom, it joins the rest of the ground wires or is grounded to the chassis?

Thanks,
Carl.

[magpies]

I believe the ground wires join at the nearside close to where the bonnet loom crosses to the chassis and connects to an earth stud nearby. I would strip off the binding to that portion of the loom to check.

[greymrj]

So much depends on the history of your car I am afraid.

Not sure which S you have but certainly on most of the ones I have seen the connectors from the headlamps/sidelamps/indicators to the main wiring were by a whole lot of the old bullet connectors. There are of course more wires than there would be on a steel car in view of the need for earth wires to remote earths. By now these connectors will usually be a corroded mess and will almost certainly have been replaced....the issue then is who replaced them, what with, and how well did they do it? I very much doubt your lights wiring will be as original.

There is also the issue that the cables are not very well secured and the regular flexing they get, which they wouldnt get in most cars, does damage wires. I had one break on Eurotour and found another with at least 50% of the core broken.

There have been posts in the past about different methods of providing connections, particularly forms or removable socket connections, between bonnet and car. There are loads of better quality connectors available now and lots of different ways of going about it.

I would say there are two crucial points.
1.Do not rely on earthing all your lights through the wiring harness, the earths may be a long way away and may be weak. Introduce a new and substantial earth (or earths) for the lights as close as reasonably possible to the bonnet. There are a couple of good locations, including the main chassis/engine earth point. On a steel car the earths would be multiple and usually close to the light.
2. Do not rely on any crimped connectors. The front wiring is very exposed and no matter how well crimped water will get in and start corrosion which will eventually affect the resistance of the circuit or break it altogether. Solder every connection and waterproof every connector.

[v8s4me]

Ceejay73 said:

.... I can obviously work around this by just throwing an additional ground at it but the question is have any of you ever stripped back this section of loom ....

Having spent many hours on those connections, and assuming the rest of the lights work OK, I recommend leaving the loom well alone and simply run a new earth wire to the chassis. Once you start stripping back the cables you'll probably find the wire has gone green and deteriorated, so finding a sound bit to solder to might be tricky. Keep it simple and keep driving

[DamianS3]

Yea replace if you can any earth crapness takes voltage away from the headlights so nice new low resistance earths can make a huge improvement. My LED headlights are pretty tollerant of low voltage but I still did this,, the old earths were green no matter how far back I cut them

Not sure I agree on soldering it makes the wire brittle a nice crimp on a water proof connector is fine for me.

Enjoy

Damian

[Ceejay73]

Thanks for the replies chaps.
Turns out the break in the wire was very close to the multi plug so an easy work around.
I decided to do as Joe suggested, (kinda).

v8s4me said:

Keep it simple and keep driving

Bypassed the multi plug as a temporary fix. I can look at this again in the future but for now just want the car back on the road.
It's been sooooooooo long since I have driven it the anticipation is driving me .

Cheers,
Carl.