Switched from ac to heat and now ac doesn't work.

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Friday morning on the way to work while on the highway I switched the temp slider in the mr2 from ac to heat. The heat never really got hot unless i turned the ac compressor off. After work, when leaving, i slid the slider back to ac and it would not get cold. Only if the car was idle would the ac cool off. Once you start moving it gets luke warm. Ac worked fine before switching to heat and back.

In the past I have had to slightly recharge the system and the ac used to not be cold on the highway until it was recharged. Recently, after that recharge, the windshield has been fogging up after a couple of days of using the ac. No I don't have a heater core leak. Any ideas about why changing to heat would mess up the ac system? Maybe not charged enough and changing to heat somehow made that pronounced?
 
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Sounds like your slider cable got messed up somehow. Run the AC and feel the metal pipes under hood, one should be cold.
 
Originally Posted By: TinyVoices
When you say heater valve do you mean thermostat?

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No, he meant heater valve.
 
On our 96 Tercel the temp has a slider and it seems to control a door. I don't think it has a valve on the coolant line. Our 93 Celica has a dial temp control with more resistance and I believe it controls a valve on the coolant hose. When you move your slider can you hear a door slap back and forth? Your door or valve may not be closing completely.

The fogging may be from a clogged ac drain. You need to find the drain and make sure water is draining from it. Keep the dash on fresh air before you shut the ac off.
 
I actually just took out the glovebox and noticed when sliding the temp slider nothing was happening with the door arm. Upon removing the controls I found the cable for the slider was moving free because it had come out of its retainer so sliding the cable was moving the whole deal, not just the cable inside thr sheath. Bent the retainer clip so it would put pressure on the cable, reinserted the cable, and all seems well now. Thanks for the suggestions everyone.
 
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