Truck won't crank using key. Thought it was the battery and replaced the terminals Cranked right up. Taillights weren't working so checked fuses and now it won't crank again. Jumped the cylinoid and it turns over but won't start.

 

I'd go back and work on the terminals again. Looks like that fixed it once. Might be bad/dirty connections.

 

More details needed, engine? Automatic or stick shift?

You check the wires that go to the starter good?

 

Stick, V6 4.2. we put a code reader on it and it came back P1000. But can't drive it to complete the drive cycle because it won't crank. Going to try to jump the cylinoid one more time.

 

Truck cranked! Played with fuses under the hood and when we got to F103, a 50 amp FMX/JCASE, Junction Block Battery Feed, it felt a little loose. Wiggled it around a bit and reseated it and bam. We are in business. Haven't turned it off yet. A little afraid to.

 

F103 doesn't have anything to do with the starting circuit. It can, however cause a lot of other things to not work. If you were able to connect a vehicle-powered code reader to the DLC and it connected and read, there was nothing wrong with the F103 circuit at that time. While you may have taken care of something that wasn't ideal, it wasn't the underlying cause of the reported problem.

 

There are two ways to "jump the solenoid". Overall, signs might be pointing to a bad starter relay (aka cylinoid or solenoid). If battery power to the small terminal doesn't work, but jumping the big terminals does, that's a sign.

 

If it is a manual transmission you could have an issue with the clutch pedal position switch.

 

That is what I was thinking if it didnt crank, but he said he got it cranking.