the Starter runs all the time ....with key in off position when hook up battery the starter starts to engage but doesn't turn engine over what would cause this to happen ?

 

Try removing the starter relay from the under hood fuse block. If it stops the relay needs replacement.

If it’s still doing it, disconnect the solenoid control wire from the starter. If it stops the solenoid wire is shorted to voltage.

If it’s still doing it, the starter solenoid is shorted and the starter needs replacement.

 

after checking fuses and not diagnosing the problem I tried the old stand by and hit the starter with a 22 oz estwing hammer and it stopped. Turned the key on and the truck started but problem recurred soon after , so I then changed the solenoid on the starter and seems to correct the problem