I know several people have asked about grid heater times and when it starts... Well here you go...
GRID HEATERS
Above 59*F ........................ 0 Seconds ............................ No Post Heating
15*F to 59*F ...................... 10 Seconds .......................... Post Heating
0*F to 15*F ........................ 15 Seconds ......................... Post Heating
Below 0*F ........................... 30 Seconds ......................... Post Heating
Remember block heaters tend to offset the intake air temp so be aware that block heater will do this.
Also be aware that there is 2 grid heaters and during the pre-heating both elements are used during the post heating it might be 1 or 2 depending on temp at the IAT. Now each grid heater is 95 AMPs a piece for a total of 190 AMPs total draw so this is why is so critical that your batteries are strong in the winter time!