When I start my 07.5 and the on board temp display is like 45 or so the heater light come on it kicks in grid heater as it should. after start it usually kicks in 2 or 3 more timeshowever after it’s up to operating temp and I shut motor off and restart it still does the same thing however light does not come on but grid heater distinctly kicks in 3 times. Why no light? Why 3 times, why is it kicking in when already up to temp?? Could it be in the tuner?? Anybody got ideas??

I guess a better question is what controls the grid heater? I read somewhere that the computer takes air temp reading as well as coolant temp reading, then decides if grid heater is needed. If that is the case then maybe the coolant reading isnt being conveyed when trick is warm. But I also read that it goes on air temp alone??????

27 minutes ago, Mega John said:

I guess a better question is what controls the grid heater?

 

Preheat is controlled by the IAT sensor. Post heat is controlled by the battery temp sensor

Ok thanks I will start with checking these sensors and connections and see if I have any luck there. Hopefully it’s something easy like that. I was also talking with my cousins husband who manages a big diesel repair shop that said it could be something in the programming of the tuner. It’s a anarchy mercenary tuner. Truck Grew up in Southern Florida so I doubt grid heater has seen much if any action in its 12 years of life.