Why does the temp on my cherokee rise? and ac question?

not sure about the a/c. but i have a 90 cherokee and ive had to replace the thermostat like 4 times. when those go bad it doesnt regulate the engine temp. OH! also, check your serpintine belt. if it is too loose you might be getting some slippage. the serpintine runs everything in your jeep including your a/c. both are a cheap fix, i think a new thermostat runs about 150 after labor. and a new serpintine will run about 90 or so after labor.