Went to start the truck this morning temp was 35deg and no glow plugs. Truck sat at work for 8hrs and went to leave and the glow plugs activated. It was 55 degrees. Truck then sat for another 5hrs and no glow plugs. Temp was 48 deg. What's up with that? All times the intake heater activated.

Just curious.

 

I'm confused. What do you mean no glow plugs? The cummins does not have glow plugs! The pre heater will heat the intake air, fuel and combustion chamber........

 

Glow plugs are only found in sissy pickups.

 

Do you mean the block heater???

 

My bad, I see the coilly que in the dash so I assumed it was for glow plugs. In the afternoon the outside temp is 50-60 degrees and the pre heater will be on. Is this common? After the truck has been sitting. When I first got the truck last summer I never seen the indicator light for the pre heater until the fall, now it appears to be on at the wrong time. Who knows it is probably me. I have had alot of issues with this thing.