MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGA - Light switch wiring

Maybe someone can tell me how you get four red wires into the S1 wire connecting post on the light switch? The hole is right for just ONE of the larger gauge wires. How do I get another large gauge wire PLUS two small wirs into that tiny space? Thanks!
Robert Maupin

Bob,
You might consider putting your head lights on a relay. The dimmer switch on the “A” is strong enough that you don’t need a relay for both the high and low beam circuits.
David Werblow

Thanks Dave,

Probably shouldn't be trying to do the electricals myself as I have no idea what you're suggesting. However, that's way I'm doing this restoration to begin with....I don't know enough to know I can't do something. So, if you could explain your suggestion in another way? I'm still trying to figure out how they did it at the factory. Having twisted the four together, the combined thickness is about two times larger than the hole provided. I'm doing the dash wiring prior to fitting the body to the frame. Having the body tub sitting up on jack stands, I can sit on the floor and the back of the dash is very easily accessed. Beats lying on my back trying to work around the tranny tunnel. Thanks in advance for your suggestions and any others that might reply to this thread. Cheers!
Robert Maupin

I can't remember how I did it but I offer this.....
When you twist the wires, you make them larger. If you are having problems, try straightening each one out, and put them in one-by-one before tightening the screw.
Chuck Schaefer

That's a thought Chuck. I'll give that a try... I was think I'd look for a crimping pole/connector large enough for the four wires, solder the four to that, trim the end down so it would fit into the hole?
Robert Maupin

You can also solder all four to another wire and then it to the switch. A couple inches of 10 gauge wire and some heat shrink tubing would do the trick.
R J Brown

First note is, there was not originally any "fat" red wire in the harness. Mine has all thin red wires. In recent reproduction harnesses one wire was changed to thicker gauge to help identify it separately from the others. This is the short wire that runs from lighting switch S1 to the fog switch. Both ends of this wire may emerge from the (repro) harness in the same spot or very close together. When all wires were same size you needed a test light to figure out which two wire ends were common. With this wire being "fat" it is visually identified.

This doesn't help the cause of installing multiple wires inside of one terminal, but note that the two "fat" wire ends should not be connected to the same switch anyway. This "fat" wire runs from the lighting switch to the fog switch. If you connect both fat ends to one terminal you have something that won't work.

The next trick is to install one of the small wires onto the fog switch along with the "fat" wire (all being common on the same circuit). This leaves the lighting switch S1 terminal with one fat wire and two thin wires, and the fog switch input terminal with one fat wire and one thin wire.
Barney Gaylord

Hey Barney,

The harness I was provided by SF, has four wires, two heavier gauge and two lighter. The wiring diagram in my manual indicates four red wires going to the lighting switch (17). This harness also has a thicker red/yellow and lighter red wire, which according to the wiring diagram, is used at the for lamp switch and comes out at a different point in the dash harness. I'm not running fog lamps so I just pull these up and out of the way. I am going to use a Lucas back-up lamp however.
Robert Maupin

I'm with Barney on this. You can connect a pair of the red wires to the supply side of the Fog lamp switch. This was how my original harness was connected.

The red/yellow wire is on the switched side of the fog lamp switch.

John
John Francis

This thread was discussed between 20/02/2010 and 21/02/2010

MG MGA index

This thread is from the archive. The Live MG MGA BBS is active now.