Hello everyone, I'm a newbie to this site and I'm hoping you can help!
I bought an 84 f150 4x4 302 auto a few months ago and I've been slowly repairing/replacing most everything since....
I'm pretty familiar with these trucks (third one so far..) and I'm no stranger to Fords but I've come across a problem I've never had the pleasure of experiencing before.

Intermittently, when starting the truck the starter will not stop. It stays energized (cranking) until I can get the battery cable disconnected. Luckily each time this has happened it's been in the driveway, and the truck hadn't fired up. Is this a starter relay issue or a possible ignition switch problem?

There's a little more to the story - This truck seems to have 25 years of "modifications" performed..... I proactively swapped out the starter relay with one I had from a previous project (67 390 mustang coupe). The starting issue didn't occur prior to this - I swapped the original truck relay back in yesterday and haven't had the problem return. However - I can't go too far off the jackstands.... the entire front suspension and axle is removed, getting a bushing/bearing/brake overhaul. 25 years of 6in sus. lift and 35" tires will wear stuff out!

I'm thinking possibly my "good" relay off my shelf wasn't really - any thoughts?

 

I have heard of relay contacts sort of spot welding themselves together as a symptom of end-of-life; that you could knock on the relay with a wrench to make them let go.

Perhaps the relay in the truck was not the correct one but at least it worked.

 

I am having the same problem. starter won't stop trying to crank. even when i take the key out. 86bigred replied back to me saying it was the voltage regulator. i think the voltage regulator on mine is the factory one so it probably needs replacing after 20 some years. and it has a fairly new starter and brand new solenoid. so i think the voltage regulator is my problem.

 

My 82 F-150 did that to me not long after I got it.
It had an Autizone starter on it.
I put a NAPA starter on it and no more problems. Knock on wood.
Man I got it from tole me he had recently put a new starter on it.
I think I have had the truck for about 7 years now.

 

Thanks everyone, I'm hoping my problems have gone away... I'll find out more once I get the front suspension put back together and put a few mile on it. I know I am able to elimate the starter as the issue, as it did it with the old starter and the new one.

Hopefully it'll be rolling again after next weekend.......