OK now my 4.6l Mountaineer won't start. Turn the key and it won't even try. I've confirmed that the starter relay clicks when the key is turned to start. I didn't see any fuses for the starter circuit in the under-dash panel. The 50amp fuse in the main box under the hood is good. I've tried both keys thinking maybe it was a security bug....no dice. Here is where it gets good. If I leave the key in the on position and climb under the truck with a screwdriver and jump power to the soleniod from the hot on the starter THE TRUCK STARTS. Doesn't that rule out bad starter? If the relay is clicking shouldn't the key be sending juice to the soleniod? Help me please?!!??!!?

 

just because the starter relay clicks doesn't mean its working and making enough contact to sent enough amperage to the starter.

you could have a bad battery cable or connection at either the battery to relay or the relay to starter. a bad relay. or you don't really have any voltage to the relay in the small signal wire to actually close the relay.

My guess would be a bad starter relay. either bad contacts or a weak coil.

a quick test is to jump across the 2 big posts on the relay. it should crank.

 

I forgot to mention that I switched the starter relay around with the blower motor relay to see if it was the relay and it still didn't start. Sorry for leaving that valuable info out. I will still test with the method you've given as it could rule out not enough signal to properly close the relay. The relay clicks pretty good but you never know. Thanks. And keep them ideas coming.

 

I'm not sure on an explorer but the starter relay should be in the engine compartment and should look like this....

you didn't swap a little square relay?

 

On the Explorer/Mountaineer there is a starter relay in the under hood circuit box. The relay is what sends 12v to the solenoid.

I found the problem. The connection to the solenoid went south. The wire pulled away but still LOOKED to be connected. I crimped on a new ring-terminal and hooked it up. She is running like a champ now. Thanks for the help. I hope I can return the favor someday.

 

at least it was a simple fix.