heater/ac not working
 

so i just bought a bravada with 350k miles. i have worn myself out trying to figure this out. the hvac module will work as far as the fan switch. anything else good luck it also blows HOT all the time. its starting to get warm outside and i want my ac back lol i was wondering if there was an way if the switch is bad if i can just put a blazer switch in im not to worried about the auto temp and everything i just want to pick my tempature lol and yes she runs like brand new this is he only issue i have had any help is appreciated