Alt wires for kill switch

Stock alternator is 65 amps, so a fuse or circuit breaker in that range is what you need.

The circuit breaker/fuse wiring is simple. The black/orange wire goes on one side of the circuit breaker/fuse and the other side goes to the wire that connects to the battery cutoff switch. The wire from the circuit breaker/fuse that goes to the switch should be on the same side of the switch as the battery. Then when you open the switch, the alternator doesn't create transients that can damage the electrical system. That way, the alternator will loose power for its field windings and quit putting out electricty when you turn the switch off. Ford alternators must have power to the field windings to make electricty.

Rear mounted battery ground wiring. Follow this plan and you will have zero ground problems.

One 1 gauge or 1/0 gauge wire from battery negative post to a clean shiny spot on the chassis near the battery. Use a 5/16” bolt and bolt it down to make the rear ground. Use a 1 gauge or 1/0 gauge wire from the rear ground bolt to a clean shiny spot on the block.

One 4 gauge wire from the block where you connected the battery ground wire to the chassis ground where the battery was mounted up front. Use a 5/16” bolt and bolt down the 4 gauge engine to chassis ground, make sure that it the metal around the bolt is clean & shiny. This is the alternator power ground.

Crimp or even better, solder the lugs on the all the wire. The local auto stereo shop will have them if the auto parts store doesn't. Use some heat shrink tubing to cover the lugs and make things look nice.

The computer has a dedicated power ground wire with a cylindrical quick connect (about 2 ½”long by 1” diameter. It comes out of the wiring harness near the ignition coil & starter solenoid (or relay). Be sure to bolt it to the chassis ground in the same place as you bolted the alternator power ground. This is an absolute don’t overlook it item for EFI cars

Black 93 Fox said:

I already have the box mounted and kill switch pretty much done. Only thing left is to run the wire back from the alt. I see I need to splice the orange/black wire to a 2ga wire back to the kill switch. My question is wont I need a circuit breaker or something also back there? If so where do i get it and what type do i need like how many amps or what ever does it need to hold. Also does any one have a wire diagram of how to wire the circuit breaker.

Thanks, Black 93 Fox

Click to expand...

I dont believe you want to splice into the black/orange wires when going to the kill switch. as that would still provide power to the starter when you hit the kill switch. I just did my battery swap this past winter. This is how i did mine. The red are positive, the Black are grounds. I ran 1/0 wire for all my positives and grounds. I think i used 1 or 2awg wire from the altenator to the switch. This way when i hit my switch it doesnt power the starter solinoid. Works great! I also ran my ground right to the back of the cylinder head and ran a few more off to various parts on the chasis.

hope this helps. its a crude drawing sorry lo