Wiring Question

I recently fried my starter, the relay / solenoid and battery, as well as melted the starter cable wire.

Installing my new parts, I found a brown wire from the harness tucked down and behind the battery, while the other wire (yellow, orange, red/blue strip, etc..) run to a connection point.

The only modification i have done to the electrical system is installation of a Pertronix ignition. I do not have radio installed. All the electrical components are working except the dome light.

Can someone tell me if this wire should be connected, and if so, to what? Or is no longer needed?

Many thanks

Need a little more info on your wiring - factory , aftermarket , size of wire , type of connector - etc.
Frying the starter , relay and battery used to be called " the threefer " - starter shorts out and wipes out the others.

Thanks SHX669. I thought i was going to upload an image but realized I wasn't able to do so directly into the thread.

It is stock wiring , but I'm not sure the gauge. Its the same thickness as the other wiring in the harness. Will check it when i'm home tonight.
The end connector is the ring type, same as the wires connected to the smaller posts on the starter relay.

If it's a small brown wire and looks like it could connect to the small posts on the starter relay it's probably the Ignition resistor bypass wire for the coil. If so it goes on the small "I" terminal on the starter relay.

Justafordguy said:

If it's a small brown wire and looks like it could connect to the small posts on the starter relay it's probably the Ignition resistor bypass wire for the coil. If so it goes on the small "I" terminal on the starter relay.

Click to expand...

Beat me to it.

And yours may be off and tucked out of the way if someone has changed your stock ignition system to an aftermarket that uses full 12v instead of the factory resistor wire.

The other colors you mention though, are a little odd for the starter relay/solenoid and may be causing you some trouble.
Do you also have a modern internally regulated alternator? That might explain some extra wires.

Usually (from the factory a stock starter at least) the starter relay on a '75 has only these wires:

1. Large cable from the battery positive.
2. Large cable down to the starter.
3. Small Red w/blue to the left side small terminal (sometimes marked with an "S" nearby). This is the wire from the key and the neutral safety switch (on an auto trans) that energizes the relay and cranks the starter.
4. Small Brown wire as described already.
5. Small Yellow wire on the battery side (powers the horn relay on a '75)
6. Large Black, or Black w/yellow, or Black w/red thick jacketed 10ga wire that powers all the accessories and allows the alternator to charge the battery.
It's the same wire as attached to the back of the stock alternator and usually has a yellow stripe at the alternator.

With a fully updated ignition the Brown wire may not be needed.
With a high-output alternator the Black w/yellow wire is not used and instead a wire directly connects the alternator to the battery or starter relay/solenoid.
With an internally regulated alternator your old voltage regulator will not be used, and those wires may be tucked up around that corner as well. They would be the Orange wire, the Green w/red wire and the Yellow wire(s).

If any of these conditions are present, you may want to verify every wire is where it should be.
You can post images in your garage without becoming a contributor for the 12 bucks a year.

Did the wires get fried after you did any work on the truck? Anything new added to that corner or anywhere near any of the wires?

Paul