that about sums it up. my grid will stil cycle with temps in the 60's F. the grid heater will also cycle on and off even after the engine is started, hence the lights dimming and if the heater fans on high you will probably hear it slow down:welcome:
The Grid heater in our cummins engines is a dual heating element that is sandwiched between the intake horn and the cylinder head, heating the air giong into the engine. it's powered by two large relays on the driver's fender, and is ECM controlled. when the ECM reads 55 deg. F or lower at the intake air temp. sesnsor (IAT) it energizes one or both of these heating elements, depending on how cold it is.
A glow plug system works much the same way only the heating element protrudes into the combustion chamber much like a spark plug.
hope this helps, any more questions don't hesitate to ask.:thumbsup