Just to confirm, the on/off/on/off grid heater cycling everyone is referring to is occurring while the engine is running, right? In our situation, the voltage cycled up to 14.7v, down to 12.1v, up to 14.7v, and so on, every 1-2 sec, about 4-5 times right after starting the engine. I'm used to the grid heaters activating just before starting the engine in cold weather, but wasn't aware they may continue to operate after the engine has started.
Is there a particular ambient temperature where grid heater cycling (while the engine is running) starts occurring? Never had this occur in temps down to 25-30 (just moved to the mid-west; we're experiencing our first "real" winter with the truck). Ambient temps were just above zero when the voltage cycling I mentioned in my first post occurred
