I have a 2006 f350 6.0 that I have owned since 2010. It has always been a good reliable truck. I spend most of my time on FTE over in the OBS section so this will be my first post here. I hadn't used this truck in about 6 months and went to start it up and the starter just clicks. I tried putting in a known good relay and I pulled the starter and tested it on the bench and it worked so I put it back in and click. I ran a jumper from negative battery to starter bolt to insure good ground ground in case the negative cable was bad, still clicked. I then jumped the terminals on the starter and it turned the engine. Went inside the truck and turned the key and it cranked and fired up. I let it run for about 10 min and shut it down. Went back out several hours later to try and the key and it fired right up. The next morning I tried to start it and click, no start. I tried jumping the solenoid terminals and it turned the motor. Back in the cab and key fired it right up. What could be going on here? Thanks I'm advance for any help. I replaced the starter with an O'Reilly starter not long before I parked it 6 months ago but I know with how new parts are anymore that doesn't mean much.

 

The contact disc within the solenoid, mounted to the top of the solenoid, is not making full contact, probably.