40 Ford Ignition Woes

[glennpm]

The contacts in the switch aren't robust enough for much amperage draw. A good fix (in my opinion) is to install a relay to power everything up through the switch. Going this route, removes the load on the contacts. The switch now only activates the low amperage relay coil.

The relay is a good change.
I have a master battery cut-off switch on the seat riser of my '32. Most of the time I turn the ignition switch on and then flip the master switch on to protect the ignition switch.

 

[Drbrown]

I'm a member that likes electrical relays and advocates the use of fused circuits. True its not stock but one must decide for them selves whats more important - originality or safety. A worthy safety goal is to get the larger gauge high-amp capacity wiring out of the passenger compartment where if worn or damaged it could cause a fire (had that happen) or hazzard during a serious vehicle accident. In addition to the ignition switch circuit itself, I also installed relays AND FUSES in my engine compaartment for electric fuel pump, headlight, parking light and fog light circuits. Otherwise, if you have a heater, get its electrical source off the ignition switch if its so wired, and fuse it. Disconnect the cigaret lighter. An added benefit is that the high-amp supply wiring between the battery and device is shorter .... slightly less voltage drop. Re Master Battery/System Shut-off Switch: Mine is mounted through the firewall.