My 99 4.3 w engine truck has only 52k miles, owned for 2 years, normal problems, door pins, water pump and so on.
The truck runs perfect, gets good gas milage, but now a new problem.
When its cold, the truck starts and runs great, after it gets to operating temperature and its shut off it will not crank over. After 30mins or so after it has cooled it will start again.
I know some guys will say bad battery, the battery is GOOD, next will be solenoid on starter, i have shorted out the starter terminals and it will crank over fine that way but not start probably because fuel pump and ignition arent energized. Passlock system on the dash turns off normally when the key is turned.
Im thinking it must be the ignition module failing, i know they can when hot.
But is the starter circuit somehow routed through the ignition module?
Anyone know, Steve.

 

You might (BE CAREFUL) try jumering the solenoid with key on. I take it it cranks fine when hot or cold.

 

Yes it will crank over when hot or cold if i short the terminals on the solenoid from the permenently hot [from battery] to the switched terminal [from key]Another clue is, if i turn on the headlights [when engine is hot] then try to start it the lights DONT dim, it just doesnt crank over.
Some part of the circuit from the key is not reaching the solenoid.
Ive also tried moving the shifter from p to n to make sure its not the tranny switch

 

So the starter doesn't crank when hot from the ignition switch?

 

Correct

 

It could be the soleniod. I know you pop a screwdriver across it, but the switch contacts inside it are probably burned. Heat is the problem, I'd bet on solenoid.

 

Thats a possibility.
I also tried a cable from positive post on battery for a direct 12v source to the solenoid switch terminal and it cranked over when hot, would it still turn over if the contacts were burnt?

 

You're forcing a direct voltage/current with a screwdriver, as opposed to a swtich. I still call solenoid.

 

Thanks for the imput Kevin.
I will try a new starter, will let you know the outcome!

 

Tried a different starter, not new but a proven good one. Same problem.
Only thing left in starter circuit that is heat affected, is the ignition switch.
They are KNOWN to be affected by heat, right?