Q: Q: My AC

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When I first start my car and turn on my ac it always immediately blows cold til about 15 to 20 mins after, it'll just start blowing regular air, it'll stop blowing cold. When I cut the car off for a while and start it back up it blows cold again until about 15 mins so I'm not sure what the issue is but it's starting to get really hot here in Houston so this has to be fixed asap. Please help. BIG THANKS!!!

My car has 148000 miles.
My car has an automatic transmission.

The evaporator is freezing up due to over-cooling. There is a thermistor on the evaporator (behind the glove box) whose function is to prevent the surface of the evaporator from getting below 32F and icing up. It should be cycling the compressor off, but your’s doesn’t. When the evaporator ices over, the A/C gets warm. After the ice melts, it blows cold again until it ices again.

You need the evaporator thermistor tested and probably replaced. If you need help with this, consider getting some assistance from a qualified mechanic who can diagnose your A/C issue and replace your thermistor if necessary.

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