Grid heater operation

[needlenose]

Does anyone know how the ECU manages the grid heater? As in:

1. What temps does it use to engage the heater.
2. How long does it operate the heater per cycle?
3. What interval does it wait between cycles?

I swapped a 1st gen into a '94 F350 CC about 8 years ago, so I don't have the ECU anymore. I'm looking to write my own using an arduino. I'm tired of the 20 minute battery-roasting start process every time it gets down into the 30s. I could probably just use a momentary switch and count my fingers, but that's not nearly as cool.

Thanks!

[cougar]

I believe the grid heaters will start between 40° and 45°. It uses a cycle down timer, that is the on time decreases while the off time increases with each cycle. The total duration depends on how long it takes to reach a minimum coolant temperature. The colder the temperature, the longer the whole duration takes. At least, that is how it works on my truck. Here in Alaska, it may take up to 5 miles before it will stop cycling.