Mechanics

A/C BLOWING HOT AIR

2005 Nissan Altima • 160,000 miles

2005 Nissan Altima 4 cyclinder
My freon is full but when I turn my a/c on it blows warm air. Then it may kick on to cold after a while, then kick back to warm. Someone told me it sounds like it is short cycling. What do I need to check and replace? I have already replace the low pressure valve.
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Kelly030
April 30, 2013.



First thing you need to check is when problem occurs, and goes away, does the A/C compressor stays engaged.

Next is to check the air mix door actuator, is it changing to heat rather than staying with A/C.

Check for trouble codes within the A/c circuit.

KHLow2008
Apr 30, 2013.
The a/c compressor is disengaging, and it is not switching to heat. Do u think it could be the sensor on the a/c compressor?

Tiny
Kelly030
Apr 30, 2013.
There are so many possibilities and I am not going to guess what is wrong. Testings are required to find the cause.
What is the idling speed? Does compressor stay disengaged when engine speed is increased?
What are the high and low pressure reading?
Did you test the compressor clutch and its relay?
Have you checked for trouble codes?

KHLow2008
Apr 30, 2013.