my 02 f-250 7.3L the glow plugs are staying on after the engine is running and do shut off when i shut the truck off does any one know what would be causing this

 

Are you sure the glow plugs are staying energized or is the lamp just not going out?
The glow plug lamp is independent of the glow plug relay.

 

yes they are staying on i have batt. voltage on the output side of the relay any time the key is on but when the key is off the relay goes to open. I just found a wiring diagram and it looks like GP relay is PCM controlled so i believe i may have a bad PCM thanks for you reply

 

Just want to touch base on this one. Yes , the PCM does determine if the GPR is activated, but the PCM takes some of its info for that from the EOT, engine oil temp sensor. If that sensor is out of range, not entirely, it could cause the PCM to think the engine is cold and keep the GPR activated. Its worth checking it out. If the sensor is way out of range it should turn on the MIL. It could be off, but not enough to cause the lite to come on.