March of 98 build date 24 valve no wait to start and no preheat on the intake heater post heat cycles are working . Time for a new ecm ??
Have started a lot of times at 30 below zero and not plugged in on both trucks why wouldn’t you want it ? Rather use ether ?
I think what @Ozymandias was eluding to was that for the vast majority of engine starts, the grid heaters are not needed, especially for post cycling. I have modified mine to be activated by me with the use of a momentary switch.
Regardless, the real concern is your wait-to-start light is not illuminating when the ignition switch is turned on. That could be an ECM issue. Have you checked for any stored codes?
- John