random no start

[Torinoman]

02 F250 Diesel randomly wont start. I turn the key and get nothing. Turn the key all the way off and try again and it starts right up. This only happens a few times a week.

The battery terminal are pretty fucked on the positive sides and I plan on doing something with those but I don't feel like they would cause such an intermittent problem. If it were the terminals it would be less random right?

Could it be a relay being a spaz? The starter itself? Sometimes also the starter gear won't engage but it will spin, and I don't know if thats related.

[shumpertdavid]

I'd start with the cables. Also, you have an intermittent no CRANK, not no Start. If it's a stick you could have a possible problem with the clutch switch. Best was to help diagnose the problem would be with a wiring diagram for the starting system and start at the starter solenoid and work back. The little wire to the starter must have power when you try to crank the truck.