F-150 starter won't disengage

AlChalmers10 · #1 (**permalink**) 07-01-2008, 10:27 PM

Hi,
I have a 91 F150 with a 300-6 and a five speed. Went to start it tonight and it started fine, but the starter would not stop cranking even when I turned the truck off. Had to pull battery cables, but starter was fried before I could get cables off.
My question is, would that be a bad ignition switch or a bad starter, or both? I know I have to replace the starter, but will I also need an ignition switch? If so, where do I find it on the truck, how do I replace it, and any idea of cost? Any help would be appreciated. Thank you very much.

MisterDave2 · #2 (**permalink**) 07-02-2008, 02:03 AM

Hey Al, welcome! I don't have a 91 but wiring is kind-of up my alley. Probably the solenoid arced or burned shut, staying closed way to long, doing it's job too good. I think it's next to the battery, can't find my Haynes book, but your local AutoZone etc. should be able to help you with that or do a search here. I doubt if it's the actual column key switch, but it's possible. Also, maybe the starter is actually still good but just overheated, don't know if it has a thermal switch inside to shut it down. Just be careful because all this stuff runs hot power right from the battery so keep the battery disc. until you're better sure what's going on.

88n94 · #3 (**permalink**) 07-02-2008, 02:47 AM

I agree with MisterDave2, it's probably the solenoid. It wouldn't have been a bad starter in the first place, as the starter has to get it's power from somewhere. The solenoid should be behind your battery, it's what the other end of your positive battery cable connects to.

Lazy K · #4 (**permalink**) 07-02-2008, 08:17 AM

Before you install a new starter or reconnect your old one you must find out what the problem is. The other guys could well be right. However there is the possibility that the problem lies with your ign./start switch. This switch is on top of the steering column under the dash. With the battery disconnected put a multi-meter across the two big terminals on the starter relay (this is on pass. side inner fender as mentioned in other posts) the meter should read an oped circuit. If it reads a direct short then the relay is bad. If the relay checks out good unplug the small gauge wire from the relay and reconnect your battery. Using a volt meter or test light see if you have 12v between that wire and ground. If you have then your ign./start switch is faulty. Hope this helps.