A/C

[mille1cw]

My 01 XLT with rear heat/ac isn't getting cold air. Freon is up to par and AC compressor is cycling. In the cab i'm hearing a discharge of air (mimics scuba diving air breathing) every couple seconds in a rhythmic motion. Now the rear heat hasn't worked for a while now fyi. Any help would be greatly appreciated.

 

[stamp11127]

Have you put a set of gauges on it? If so what were the readings and outside temp?
I'm assuming that both the front and rear are not cooling from your post.

 

[mille1cw]

outside temp was 70 degrees at the time, the only thing i hooked up to it was a cylinder of freon recharge. There was a gauge on the top of that but besides that, nothing else.

 

[stamp11127]

Is the front a/c cooling like it should?

 

[mille1cw]

no it is not

 

[stamp11127]

Since both front and rear a/c units are not cooling that gives you a direction to head in.

A/C units have a high and low pressure switch to protect the system. If you had a set of gauges you could read the high and low pressures which would give you an idea of what is going on. The usual problem is a lack of refrigerant due to a leaking seal or a hole in the components. That will trip the low pressure switch and give the impression that the compressor is cycling.

Another problem can occur when the compressor craps out, plugs the orifice tube then trips the high pressure switch due to the blockage.

When the system is running, does the a/c line the goes to the accumulator get cold? Or if it is easier for you, does the accumulator get cold?

 

[KWT2000]

how fast is the compressor cycling?

 

[mille1cw]

The compressor kicks in for about 10 seconds at normal speed then shuts off in normal intervals. I'm going to g check the accumulator now.

 

[KWT2000]

it is cycling fast probly low on refrigerant as well

 

[mille1cw]

my mistake, the compressor spins fast for about 2 seconds then off for 8 seconds.

 

[stamp11127]

You could jump the low pressure switch connector and see if the compressor stays on for a longer period. If it does then the system is low on refrigerant. If it doesn't then the high pressure switch may be tripping. On my 99 the low pressure switch is located on top of the accumulator.