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MG Midget and Sprite Technical - Lighting issues after fitting GRP rear end!

Hope someone can help out here, I have just fitted a GRP fibreglass rear end to my '79 1500 midget, reconnected all of the wiring and found that:

indicators flash tail lights,
no brake lights when tail lights off,
when tail lights on braking dims tail lights,
front left headlamp dim and dips even more when high beam switched on!

All these things sound like an earth problem, the only area I have been working in is the boot space and the only earth there,(mounted to the boot stay) was not removed during the work carried out on the rear. I have tried removing and cleaning ths earth to no effect, the wiringloom is only 4-5 years old and everything worked perfectly prior to the recent work.

Could I have missed another earth somewhere? Could removing all the panel work reduce the earthing effect? Any other ideas?

Thanks in advance

Dave
D Prince

It will be an earth problem

the easiest and best solution for GRP sections is to earth each separate lamp unit back to the chassis mounted earth point. On my car this is offside roughly above the offside spring on the chassis rail extension section, just where the inner wing reaches the boot floor area.

As my car's back end wiring had been buggered about during her previous life as an Arkley, I have no idea whether the same point is used on other marks/models.

Always start with a "known good" set up and keep it that way unless concours is the idea. Which is obviously not an option with a GRP rear end.
Bill

Agreed Bill, Earthing would be the likely suspect.

The fun I had with IoW:)
K Harris

IIRC the main earth for the rear loom is fastened to one of the bolts that holds the rear number-plate plinth.

You need to re-instate this earth (black wire) by bolting it to the steel structure of the car (ensure good clean metel-metal contact with the body).

Without more details of exactly what's fibre-glass it's hard to give specific advise.

A
Anthony

Another vote for earthing. When dealing with non-metalic bodywork, you will have to run explicit earths to each device. Do NOT try to simply "daisy-chain" a single wire; it has to carry just as much current as all of the wires going to the other sides of the bulbs. I would advise that you create a separate loom of multiple black wires.
David "Let me tell you about my friend's dune buggy earths sometime..." Lieb
David Lieb

This thread was discussed on 30/06/2008

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