AC worked amazing all summer. At 60 it could get freezing so I would put to 65 or 68 or whatever, it would still blow cold. Then a chilly day came and I tested the heat, which works good. Since then, if I have all the AC buttons on, it blows freezing at 60-61, but if I barely nudge it up (to about 63-65) it blows blazing hot. What part do you suspect has malfunctioned? Also, a month ago AC didn't function at all, so I took it to a shop that drained the system, and recharged it with dye....
I did have a remote starter installed about a week ago...? Had $30 credit on living social that was soon to expire and so I figured why not? I read on a Toyota 4-runner forum that these clowns sometimes unplug and splice into wires...I am betting this is what the culprit is considering I noticed the issue days after installing the remote starter...
Your HVAC has a test mode where it will (a) blink out any trouble codes on the A/C button light, and (b) respond in very specific ways to the control knob positions, so that you can diagnose whether the control inputs and outputs are properly working. Details in your service manual volume 1 at techinfo.toyota.com, or you should be able to search them up out of threads in this forum if you have the time. If you can let us know what those results are, it might help to figure this one out. Cheers, -Chap