2007 GMC Envoy SLT "car heats turn ac" Questions

...I turn on the heat for one day. Now heat comes out of the vents when I turn on the Ac. Ac worked fine until I turn on the heater for one day. Now the Ac is blowing heat. Why? vent flap shutting

...CAR OVER HEATS...ALSO,THE AC ONLY COMES ON WHEN MY CAR IS TURNED ON AND IDDLING... BOTH OF MY FANS WORK AS LONG AS MY AC IS ON...IT WILL NOT OVER HEAT THIS WAY.... Temperature sendin unit needs ...

...car is started with out the defrost or ac being turned on the fresh air intake will some times turn the ac on you can turn ac off the fresh air will still be closed. what can be causing the heat to ...

heat comes on all the time, even when ac turned on heat on all the time, even when heat switch turned to off, no ac resistor bad in wiring harness from switch to heater and ac.ford had a recall on ...

...fine when i turn my car on but then when i accelerate it starts blowing warm air check heat exchanger . It is a little radiator for the AC to vent the heat away from the AC system under the

AC/ Heat is working defrost not working when i turn the heat on nothing blows out what should i do... ac as well... i put a new fuse in the AC but it blew oout sounds like a short some where, start by

turn the heat or ac on. They claim it hasnt squealed for them. However, whenever i turn the heat or ac on it squeals for about 2 minutes then stops. It also stops whenever i turn the heat or ac off???

...Turn off AC and hit auto and raise temperature but no heat. Any ideas would be appreicated mechanical or vacuum operated valve that releases hot coolant into the heater core may be stuck closed. or ...

...car it idles high sounds like it sucking lot air through air filter then goes back to normal idle but if you turn on heat or ac the engine idles high again and feels like cruse is engaged keeping the ...

...heats the car. i changed the thermostat, that didnt solve the problem i changed the ac fan, replaced it with a new one but still did the same thing.. but wen i turned the ac off the tempature is fine ...