Join Date: Nov 2008
Location: Salina, Kansas
Feedback Score: 0 reviews
You should excite the relay, that does the same thing...unless the relay is the trouble. Then you wouldn't need a heavy switch, because the relay takes all of the amperage, and the switch only pulls the coil of the relay in. There is also a fusible link, right off of the starter relay (on the passenger fender well) Sometimes they will burn mostly through, but not burn the insulation. It will look perfectly normal, and there will be voltage to the hot side of the relay until you put a load on it, then it all goes away, because there isn't enough conductor to carry that kind of current. that one was a head scratcher for me for about an hour when I first got the truck I have now. It sounds like everything works beyond the "ribbon", so the trouble is before it gets there. My next step would be to check the fusible link, mostly just grab hold of both ends, and pull firmly. If it comes apart, it wasn't any good anyway. Also with an assistant, check the voltage on GP side of the relay when it cycles on. It should be somewhere around battery voltage, if it drops to nothing, definitely check the fusible link. Just follow the wire harness back to the relay on the fender well.
1993 F-350 crew cab non-turbo 5 speed transmission
35 years a mechanic on large stationary engines natural gas and diesel fired, and other industrial equipment.