Does anybody know what triggers the grid heater relay? The ecm, or a sensor? I’ve replaced the grid heater and relay and tested all power, once I trigger the relay the heater turns on but still no wts on dash. I also put the iat sensor in a cup of ice water for quite a while to see if that may trigger it, no luck. The only thing new to the truck is efi live. 

12 minutes ago, MoparMello said:

Does anybody know what triggers the grid heater relay? The ecm, or a sensor? I’ve replaced the grid heater and relay and tested all power, once I trigger the relay the heater turns on but still no wts on dash. I also put the iat sensor in a cup of ice water for quite a while to see if that may trigger it, no luck. The only thing new to the truck is efi live. 

My advice is to go back to stock programming and see if the ECM starts turning the grid heater back on. If I remember correctly the grid heater relay trip wire is always hot and the ECM controls the relay by supplying a ground to turn the relay on.  I've seen many OEM functions quit working with aftermarket programming. Could also be something as simple as a blown fuse. Check all the fuses in the PDC.

I contacted the seller and in fact he had the grid heater turned off through efi live. Sending auto cal back for repair I will update when finished.  Thanks for the help.