Heater/Fan won't turn off..
 

As I went to the store yesterday, I started up my car and read the temp gauge read 116 degrees outside. Pretty hot. Everything was fine, I turned my a/c on. Came back home and went on with my day. This morning I go to start up my car and I had it left on low with the a/c on. I try to turn it off and when it goes to off, it passes Auto to the Off mode and the a/c turns on and it's on full blast, it won't turn off. The a/c will turn on/off and I can put it back on low to blow minimal air. I can even turn the car off, switch it to off and start up the car with it being turned off.. Anyone know a cause/solution?