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MG MGB Technical - ground (earth) locations

Is there a pictorial somewhere that shows the actual locations of all the grounding points?
Steven Rechter

It varies with model and year, for both quantity and location. But typically there is at least one in the engine bay for lights, relays and control box. One behind the dash for heater fan and wipers, and one in the boot for the fuel pump, tank sender and reversing lights. Many components earth through their physical mountings, like all rear light clusters, CB front light clusters, instrument stabiliser, and many others.
Paul Hunt

Thanks Paul.

I have a MKI that has a black ground wire daisy-chained to each instrument on the dash. Do you happen to know where that wire physically ties to the chassis?
Steven Rechter

Follow the wire! It's usually on the bolt securing the wiper motor, but after all this time things get changed and added to. For instance I always put earth/ground wires on the rear lights and the side lights.
Allan Reeling

AFAIK my Mk1 doesn't have a ground in the engine bay.

There is one under the dash near the wiper motor, as Allan says, IIRC.

I'm not able to check at the moment!

Dave O'Neill2

The instruments usually go with a couple of others to an earthing point behind the dash. On mine and others I've worked on that's a bolt unto the body under the screen, by the motor rather than on it.

The schematics show one for the headlights and a separate one for the control box for 62-64, the remainder of Mk1 seem to share an earthing point with a separate one for cabin components. After that they do all seem to come back to one point for a while with up to six wires, quite possibly the cabin, before splitting off again.
Paul Hunt

This thread was discussed between 25/01/2014 and 26/01/2014

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