| Couple things to look at:
-First make sure you don't have the dial in the center of the dash set to the "red" heat settings; it controls a little stepper motor that allows you to fine tune the air temp. I really doubt this is the issue, but ... you never know; often it's the simple things being overlooked.
Just a FYI, there is a dozen or more of those little stepper motors throughout the car that fine tune the air temp and all sorts of crap; sadly it's all getting very old so it's prone to failure. Just hope it isn't one of those ... first I honestly (even after about 5 years of owning these cars) have no idea where they are, and second it means ripping out the whole interior to test and replace them ... and they're expensive too ...
That said, I'd start by checking the actual A/C controls; if you have the fancy controls ... you know, the automatic climate control with the horizontal dials, then it's possible that's bad. The sheer amount of "stuff" that does is amazing ... bad part is it's hard to find them to swap and see if that fixes it. If it's the regular one with the 2 temp knobs and 1 fan speed knob, then I'd swap a good unit in and see if that solves anything.
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