A couple of weeks ago I drove my 2000 f250 for about thirty min. and turned it off for about 15 min and the truck would not start. It would NOT crank over but all interior lights and radio would work. I messed with the large relays in the engine compartment and it started right up. Well I replaced all but 2 relays and it was fine for a week and then did it again. The problem is I have to mess with a different one of the large relays each time to get it to work. Has anyone had this problem or knows what may be causing this problem. It happens randomly but mostly after I have been driving a while. Any help would be great. Thanks in advanced!

 

Sounds more like the starter solenoid, had a porsche once that was like that bang on the solenoid with a 1/2 drive ratchet and it would crank right up. It only did it when the engine was HOT. Next time try that before messin with the relays and see if it starts.
Does anything happen when you try to crank it?

 

First thing I'd do is clean all of the grounds from the battery's on down to the starter.
You should also have a electrical tester with you at all times so if it happens again you can test your way through the system to see where the power is stopping at. You should also have your battery's tested to make sure that they are at full capacity.

 

Nothing happens when I turn the key. No cranking or any noises from the engine. The batteries are almost brand new. Thanks I will try that.

 

Nothing happens when I turn the key. No cranking or any noises from the engine. The batteries are almost brand new. Thanks I will try that.

 

Exactly which relays did you mess with?

 

The first time it was the small black box with the 2 relays toward the firewall next to the brake reservoir and the next time it happened a week later it was the large three in the larger black box i had to mess with the one closest to the firewall. the third time I had to mess with all three a few times and then it started.

 

Hmmm. That does not make sense to me except that it seemed to work. Maybe it was more of a cooling down time while messing with them than anything else. I suppose you could test all the relays to be sure but I don't know. Maybe someone else has had a similar problem and will chime in.

 

A/C relays have been know to stick and cause a drain on the battery. Could happen to any of the relays that may or may not be related to the starting problem. Maybe there are two separate issues?

 

A/C relays have been know to stick and cause a drain on the battery. Could happen to any of the relays that may or may not be related to the starting problem. Maybe there are two separate issues.

 

The relays that are under the little black covers between the power dist. box and the brakes are Trailer tow backup relay and trailer tow battery charge. If you have 4wd the two relays under the other cover are for you ESOF. If you think any of those are the problem, just unplug them and see if it makes a differance.
I would come nearer thinking that one of your main wiring harness plugs that are near that area is trying to come unplugged.

 

I read in Motor magazine that Ford has a pigtail wire kit for intermittnt no-crank condition on some Ford cars and light trucks from 1997-2007. The kit (6U2Z-14S411-NA) is supposed to correct an intermittent open in the starter relay to starter motor circuit.