1980 F350, 400z

The other day I was checking fluids before leaving. I shut the hood and the truck died, I got back in and it worked fine... for about a mile, then the truck lost all power so I pulled over and chain towed it home. By no power I mean not even the dome light works. We tried jumping it but that did nothing.

My brother said it was probably the starter so I took it in, and though it passed all tests, it sounded like it had marbles in it (it wasn't sitting in the bearing at the end correctly) so I warrantied it. Took it home and still no power.

I read online to try changing gears with the key turned on, but I just tried turning it and it came right on! I left it sit for a bit to charge the battery a little (it wasn't dead). Today I was going to go somewhere but when I got in the key was locked up, I couldn't turn it, so I tried another still nothing, I also couldn't changed gears. Also no power, needles didn't move no dome light etc. After a few tries it tried to start, but I hadn't pumped it so it didn't start. Now it's back to just no power.

I noticed once that I could pull the ignition out about a quarter of an inch. Tried some WD40 on the key but I think it's just shot (I don't have graphite).

Would the ignition switch cause the truck to die when I shut the hood? No power at all in the truck (even dome lights?) I'm sure about the other problems. I also cleaned all the wires at the battery, starter, terminals, and I tried an old solenoid that I'm 95% sure was still good. The only spot I didn't check yet was where the solenoid goes to the frame/block(?) and back to the starter, but I changed that wire within the last 2 years.

Thanks

 

try a boost

 

Since the domelight and nothing else would work, ignore the large wiring and the starter. You have a power problem to the truck.

I would go to the large terminal on the solenoid that the battery + connects to. Underneath the large battery + wire should be a smaller wire. This wire is the one that powers the whole truck. Make sure it looks good where it's connected to the solenoid, and then follow it down in the harness. You may need to unwrap the harness, but you should come to a factory splice. Sometimes these splices corrode. From this splice, you have wires going to the alternator and also some others feeding the rest of the electrical, like the headlights, and there should be a large yellow wire that goes into the firewall and feeds the ignition switch and the fuse box.

This whole area is where you need to look for bad connections, frayed wiring, and check for voltage problems. Also in this area you will find lots of colored rubber things in the wires called fusible links. Pull on these links to make sure they are good and not corroded. When you have the problem again, turn on the headlights. If the headlights won't work, then you know the problem is nearer the solenoid in this wire that feeds the power to the truck.

 

Also be aware that the Ignition lock cylinder, is not the ignition switch.

The ignition switch is bolted to the top of the column underneath the dash and is hooked to the ignition lock cylinder with an actuating rod. The dome light is not hooked to the ignition switch so the problems you are having with the ignition switch and seperate ignition lock is a different issue.

Franklin, I think is right on the money, however I'd like to add that you...

Check the battery cables to make sure they are not corroded, and are clean and tight. Also, check the engine ground, and the engine to firewall ground cables.

 

Yes I meant the Ignition lock cylinder. I forgot to add that sometimes I can start the truck without a key in it at all, but usually not.

Yes I cleaned all the wires except the one that comes off the battery side of the solenoid. I cleaned it at the solenoid and starter, but not where it connects to the frame/engine then back to the starter. the engine to firewall wire was the first I checked.

There is a fusible link that broke off at the connector, luckily the round part stayed on the solenoid so I could identify it. It's broken straight off, not like the fuse burned out, but just broke off at the circle (the part that crimps to the copper is still in the fuse but it's flush with the fusible link. I'm guessing this is what you were talking about.

I will check these 2 things first. Thank you.

 

I would look at the fusible link... But to add some credit to your ignition thought... My wifes car kept shutting it self off ,killing the power to the car completely and blowing my ECM fuse.. Sometimes for no reason,, sometimes on a bump in the road... Finally gave up chasing the gremlin and took it to dealer...dealer came back with faulty ignition switch...I thought for sure they had misdiagnosed... But changing the switch fixed it

 

Yes it was that fusible link! Thanks a ton!