i have a mitsubishi 2001 4 cyl galant the problem i have is when the car is cold i have no problems but when it gets hot i try to turn the heater on then the car stalls can it be the temp sensor or not thanks for any help...

car stalls when heater is turned on ? sounds like an electrical problem

it' only happens when i try to put on the ac or front defogger..

Hmmm there could be a crack in one of the diaphrams that control the mode door. Is it vacuum operated, electric or cable?

it' only happens when i try to put on the ac or front defogger..
This is because of the AC...NOT the heater.

Good thinking, it may be idling too low in the first place.