Why does S-10 temp go up while idle & AC on?

How hot does it get, its okay to have the engine run a little hotter with a/c on, as long as it stays in the safe range, you can check the a/c freon or if in need have it replaced, maybe it just needs a recharge. Your truck should be r134a freon and you can get gauges and r134a your self and check, if it does to get cleaned and replaced recomend a shop do that becouse there is a type of oil in there and you need things to be at the right levels, (and they have a machine that vacuums it out) but to check and top off you can do that. Also check compressor and check for leaks.