[4RE KLR]

Mike
Just a thought here, OK

Look under the dash and see if you can find the duct work for the system. In some of my old trucks (yes, I know it isn't a car) I could actually see the cable that lead to the door that opened and closed the system that let the heat in.

Maybe, if you can get to it, you can close the door manually, and let the heat get into the cabin. Now it seems if you are just by-passing the interior of the car.

I don't know if you can get to it in your car, but it is just a thought.