I've been turning the HVAC switch OFF to stop the electric heating pump while in EV for years. No big deal to me because I don't need the heater here in FL anyway. In fact, I've bypassed my heater core so the A/C gets colder faster and stays cooler longer in EV. The vented air also is cooler so I have to run the heater pump sometimes while in EV. With the heater core bypass the electric pump can't circulate hot coolant in the HVAC system so the vent fan can still circulate cool air in EV. I can reconnect the heater core with a screwdriver in a few minutes if I need the heater. There are pictures in my photo section on Cleanmpg.com of how I bypassed the heater core on my '05 FEH. Very simple and cost a little over $10 for plugs, elbows, clamps, and a small piece of heater hose. None of the factory hoses are cut so the reconnect looks the same as stock.

The '09 FEH has a automatic A/C control system verses the manual control in my '05 FEH. I don't want to bypass the '09 heater core for this reason but I can always turn the HVAC system OFF if I don't want to run the electric heater motor in EV. I rarely turn the HVAC system ON and have a "D" battery powerred fan if I don't run the A/C.

GaryG