you do not need the grid heater. get a grid heater delete block from cummins, glacer, winspeed fbd, or others and remove the wiring between the solenoid and heater.
I've had mine unplugged for years now and can get by until the temps get below freezing. At that point I use the block heater for a few hours and the engine starts regardless of temp.
Mike
It is -5 F here the other night. Last winter we had some -30.
Where can I find a new grid heater? The posts broke out of mine, & it is currently unhooked. Don't want a fire, you know.