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MG MGB Technical - 2 brown wires in, 2 out - what does it do?

I just bought a '78 parts car to salvage for parts wearing out in my '77. Before I start tearing it apart I wanted to get it running to see what works and what doesn't.

I haven't gone through it completely yet, but the first thing I noticed was there is a connector missing from the wiring harness. Looking at my '77, it is a plastic connector and has 2 brown wires going in and two brown wires coming out, all with spade connectors (vs. bullet connectors). It is located on the right firewall, close to the fuse block, inline with the wiring harness.

I couldn't find the connector in the Moss catalog, so I don't know if it is available any more. Does anyone know a source for them?

What does it do? Is there more to it than just a 4 way connector? Temporarily I can use the one from my '77, but I don't want to keep switching parts across since the '77 is my daily driver.

Thanks,
- Phil
Philip Coburn

Are you really sure that once you get your parts car running that you are going to be able to resist turning into a restoration project in its own rite?
Marc

I think between my wife and my bank balance they will keep the project in check! (but of course you never know...)

- Phil
Philip Coburn

What makes you think it's original? It doesn't sound original, nor does it sound like it would serve any purpose, unless you were tapping the line. Unless I'm misunderstanding (always a possibility) I wouldn't worry about it.
Baxter

I think it is original because the wiring is the same on the '78 parts car as it is on my '77 daily driver. The only difference is the connector is missing from the '78 with 4 wires hanging there not connected to anything.

I'm pretty sure without doing anything, the car will not start, but I haven't had time to try yet. I will take a closer look at the wiring diagram tonight and see what the 4 wires are connected to.

One clarification, it located along the right inner fender (not the firewall as I previously described).

- Phil
Philip Coburn

Could it go to the alternator?
william fox

Just a WAG. Is the car still original, not aftermarket electronic points? If not maybe thats where it connected to.

Mike
'79B
Mike Janacek

If the piece you are talking about is about 1.5 to 2 inches long by about 1 inch wide, then it is just a connector for four power wires. I have the same connector in my 78 and it is a four way connection. meaning the junction is electrically the same point for all four wires. I do not have my scematic in front of me but that is as I remember.
andy heston

Andy,

Yes, it is as you described. I'll just wire them together temporarily for getting the car started.

Thanks,
- Phil
Philip Coburn

It is probably the double-brown that comes up from the solenoid to feed most of the cars electrics. I say 'most' as the hazards seem to have their own feed up from the solenoid (I can see some sense in that) and so does the starter relay. Why the relay does, when everything else like the ignition switch, lighting switch, fusebox and ignition relay is powered through this double connector I can't imagine.
Paul Hunt

Paul,

You are right, I took some time last night to trace it on the wiring digram and it is a feed from the solenoid to the lights, ignition switch relay and the bottom fuse (which then feeds the purple circuits). I assume the double wiring is instead of using a thicker guage wire, and this connector is where it splits off one wire to go to the fuse box.

Still not sure why it isn't just a four-way bullet connector, but I can move ahead with getting the car running.

Thanks for the help,
- Phil
Philip Coburn

Once upon a time in another life, it was a junction for a shunt to a amp gauge. I don't think it ever made it to the MGB, but on other cars this set up was used so they didn't have to run the high current wires in the dash like they uses to on the early cars.
It's just a connector on our cars.

Kelly
Kelly Combes

Only seems to be 'later' models, probably after most manufacturers were fitting voltmeters instead of ammeters, and only on North American models so possibly some local requirement.
Paul Hunt

This thread was discussed between 05/11/2002 and 07/11/2002

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