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Q: Air conditioner blows warm air.

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Got in my truck today. Warm air only blows when I turn it on. This is both idle and driving. Blower motor is new. Recharged the system about three months ago without problem. Was super cold. There was an odd smell coming from my vents over this week. Don't know if it was freon or not. Condenser fan motor is two years old. Lines are not cold when hood is popped. No signs of sweat, condensation. Something is wrong, but I cannot pinpoint what it is. I'm a big diy kind of guy. I can't do it myself if I don't know what it is. Please help. Thanks

My car has 146000 miles.
My car has an automatic transmission.

A: The most common cause for warm air when the...

The most common cause for warm air when the air conditioner is commanded on is a low refrigerant charge, usually from a leak. One way to check the charge is to have a technician attach a manifold gauge set and inspect the system pressure on the high and low sides. The a/c compressor will not be running so pressures should be equal on both sides, but if the pressure in the system is very low then there is a leak. If the system charge is about normal, the a/c compressor clutch may not be working. The clutch turns on and allows the a/c compressor to spin while the engine is running and no function from the compressor will allow warm air to come out of the vent. Consider hiring an experienced technician like one from YourMechanic who can come out and perform an a/c system check and diagnose your air conditioning concerns more personally.

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