First of all, I would suggest that you actually test all the fuses. You cannot tell by looking at them for sure if they are good or not. We had something like that happen in our Jeep. DH checked all the fuses and thought they were good, so sent Jeep to shop. It was a main fuse that was blown - everything shut down - no power to engine, radio, lights,wipers,heater, nothing. It could be just a coincidence that when you turned on the heater the fuse blew - maybe not. My daughter had a vehicle that would do that if you turned on the rear defroster. If you didn't all was good. If you did - blew the main fuse.
