sometimes it will start and sometimes not. that means nothing in the start mode but I have gages and fan come on. What I really need is a wiring diagram for the start circuit for 86 f250 with 6.9. I did look but could not find it.
thanks nick c

 

Automatic or manual transmission?

 

Its an automatic, I posted a similar question about a month ago, took nss off, took d40 with straw and shot some inside of switch then blew it out with air compressor, wow I turned sw all the way cw and nothing, turned it ccw and it started everytime in park and neutral. Is there a nsw in the steering column for the park and neutral position?
thanks nick c

 

No, the switch on the tranny is the only one. Other possibilities are the ignition switch and the relay on the fender. Tests (make SURE tranny is in PARK!!!):
* Remove the small wire/connector from the starter relay (just pulls off). Run a jumper wire from the battery to that terminal on the relay. If it cranks, relay and starter are good, and ignition switch and/or wiring to it (or fuse) are the suspects. If no crank:
* Reconnect that connector (just so you don't forget) and run a jumper wire from the battery + to the large terminal that goes to the starter. That's the terminal that has only one large-ish wire on it. If it cranks, starter is good and relay is the prime suspect. If no crank, problem is with starter, main starter wiring, main battery connections / grounds, etc.