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MG MGB Technical - Wiring Harness Routing

I'm rebuilding a 74 GT. Wiring harness (and lots of other things)was missing when car was acquired. Can someone tell me the correct routing of the harness as it goes from the rear of the car to the front? Does it go inside the car, or under it?

Thanks.
M Sadley

It goes under the car on the right side along with the fuel & brake lines and the battery cable.
John H

It goes along the underneath beside the brake and fuel lines.
Dave
David Steverson

Thanks for the info. Looks like tonight will be spent laying on the garage floor. :)
M Sadley

Have a look in the Clausager and you will see virtually everything you want to know about the wiring harness. Basically it goes down the RH chassis leg and then parallel to the brake and fuel pipes. There are moulded rubber blocks which are attached to the underside of the body by bolted U brackets and into which the pipes and wiring harness are clipped. One wire goes off to the fuel pump en route and the remainder goes through a grommet on the corner off the boot floor going back to the tail lamps, down through another grommet to the tank sender and the remainder across the rear of the boot to the other tail lamps. Very importantly however there are a bunhch of black wires and they must be bolted firmly to the back panel centre support as nearly everything is grounded at that point and can be a source of problems. Good luck with it.
Iain MacKintosh

The routing is a little different on a 1974 US-spec vehicle from that shown in the photos in Clausager's book. On a '74 US-spec B, the wiring harness is not inserted into the rubber blocks -- those hold the battery cable, the fuel and brake lines, and the metal vapor pipe from the canister in the luggage compartment. The wiring harness is held in metal "P" clips attached to the chassis leg next to those rubber blocks. On my car, the "P" clips were attached to the chassis leg with sheet metal screws.
David Pash

I thought what David say applies to all cars? On my 78 the wiring loom was held by P clips also.

The loom also passes THROUGH the fixed crossmember. There should be a hole with a rubber grommit each side. Don't forget that before putting the rest in place!

Simon
Simon Jansen

There seem to be a few variations here. Strap clips are common at the top of the chassis leg and if it's P clips because of the vapour line then that's fine. Some looms go through the cross member and others go over it supported by a larger saddle type rubber block.
Iain MacKintosh

Thanks to all for the input. Installed the wiring harness last night using your input. It looks like it is right where it belongs.
M Sadley

This thread was discussed between 05/01/2006 and 06/01/2006

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