Quote:

The Ford unit has two large posts. Battery/fuseable link to loom in, and power out to starter. It also has two small posts marked I and S. I supplies power to the coil at full 12 volts. The S is for the neutral safety switch.



The S terminal is Start power from the starter switch, the solenoid must be grounded to complete the start circuit; the I and S unit can't be used with a NSS unless there is an ISO relay in the circuit. (see diagram below)

To use a NSS with that type of solenoid you need the unit that has two unlabeled small terminals, one terminal is power from the starter switch and the other is grounded through the NSS (you'll lose the ignition boost)....the solenoid doesn't need to be grounded.

7784751-ISOStarter.jpg (3304 downloads)