A/C turned off for engine safety

I was driving on the highway all of the sudden the steering wheel became really stiff and a signal light came on that read DISCHARGE BATTERRY TURN OFF A/C FOR ENGINE SAFETY. So I pulled over because the van started to lose power. I checked under the hood and noticed that antifreeze had leaked from the water pump and the engine belt came off. So the next day I replaced the water pump, engine belt, antifreeze, and I also replaced the thermostat. So I took the van for a test drive the temperature gauge started to get to hot and I went back home and removed the thermostat. The next I drove the van without the thermostat for about 400 miles and noticed the temperature gauge was not reading and that signal light for A/C OFF FOR ENGINE SAFETY had turned on.