I recently had a problem with my 2000 4runner(A/C WORK FINE) the problem was that my heater valve broke and it wouldn't get hot when i turned on the heater (very cool). So what i did was i left it there for a good hour driving, and then i got hot again. After a couple of hours i switch over to the a/c and i was blowing out hot air too. It was like the heater was on even if the turned the climate control to cool and press the a/c button. After that i took the heater valve off to see what the problem was and what i found out was the other side where the coolant line connects to rusted out and that there was a blockaged. I cleaned everything out and my heater work perfect again, but i can tell that my a/c wasn't as cold anymore. What did i do that made this happen? was it because i had my a/c on for a while, while the heater valve was stuck open? i'm lost i can't understand this, my understading was that i need coolant to turn on my heater (fan in the back blowing) with the heater valve fix it should stop hot coolant from entering the heater core which will not create heat and will provide me with cold air. Do you guys think there is something wrong with my a/c and not with the heater valve anymore? Every little advice will help fill free to comment Thanks