When I turn on my heater, the engine cuts out. I have no problems with overheating, and there's no problem with acceleration or keeping the engine running if I don't have the heater on. There is a scraping/grating noise coming from the right side of the engine compartment (right side if you're sitting inside the car), near where the heater is. I'm going to take it to a mechanic, but I'd like to have an idea of what's going on first.

Thanks so much!