Compressor Of And On

[COOLBLAZER99]

Compressor Cycles Off And On Every Couple Of Seconds. Checked Pressure Is At 40 To 45 Psi . Bought R134a To Fill But Pressure Seems Fine. Could It Be Pressure Switch. Is There A Way To Reset System Electronicly?

[BlazerLT]

You should get a gauge.

I think the full range is around 55psi.

[Flashbac29]

I have a 2000 blazer 2wd 4dr w/ 38,000 miles... The pulsing of the AC Compressor seems to be normal operation... perhaps someone else on this board could give some insight as to what the benefit would be to have the compressor pulse.

[COOLBLAZER99]

Originally Posted by COOLBLAZER99

Compressor Cycles Off And On Every Couple Of Seconds. Checked Pressure Is At 40 To 45 Psi . Bought R134a To Fill But Pressure Seems Fine. Could It Be Pressure Switch. Is There A Way To Reset System Electronicly?

GOT A GUAGE, 45PSI IN BLUE RANGE, SHOULD BE FULL. TURNED AC ON MAX PUT GAUGE ON TESTED OK. BLOWS WARM. COMPRESSOR ON FOR 2 SEC OFF FOR 2 SEC OVER AND OVER.

[metallica21156]

i work on HVAC and its normal. it has a high pressure switch and low pressure. when the compressor pushes the 134a down to a low enough and high enough it will shut off. you will notice that if you rev the engine up and hold it at a 2,000 rpms or close that the compressor clicks on and then right off. the higher the rotaion the less time the comprssors on. but still will maintain the same pressure in the system. also all car AC systems leak. its just the way its made. also i've been told but don't think is true, that the AC compressor on cars have a life of about 10 years. if you go longer your luckey. i have a 90 chevy orginal compressor and the one in my jimmys fine as well. and the low side should be lower then 55 psig. i think when i charged mine and it was around 40 when the compressor clicked off.

[BlazerLT]

A AC compressor is not supposed to cycle on and off and couple of seconds.

It is a sign of low refrigerant and pressure.

It is not normal.

[blazes9395]

Like LT said, it sounds like its just a little low on refregerent. Add just a little more, following correct filling procedures, and you should get it. If its cycling, then the system is generally working, its just cycling on and off to fast. Is the guage you are using from one of those kits? Usually those guages can be slightly off, giving you a slightly off reading on the amount of refergent that is in there.

[COOLBLAZER99]

Originally Posted by BlazerLT

A AC compressor is not supposed to cycle on and off and couple of seconds.

It is a sign of low refrigerant and pressure.

It is not normal.

YEAH CHEAP KIT. GOT ANOTHER ONE FROM WORK, BRASS QUICK CONNECTS ETC. MADE A JUMP FOR PRESSURE SWITCH TO KEEP RUNNING SO COULD FEED 134A INTO SYSTEM. EVERYTHING SHOULD WORK NOW.LET YOU KNOW IF WORKS.

[metallica21156]

some systems are supposed to cycle. its the way they are built. i have a 95 jimmy and it cycles. my parents 98 pick up cycles. ITS NORMAL FOR SOME SYSTEMS. don't think its true. ask gm. they will tell you.

[BlazerLT]

Originally Posted by metallica21156

some systems are supposed to cycle. its the way they are built. i have a 95 jimmy and it cycles. my parents 98 pick up cycles. ITS NORMAL FOR SOME SYSTEMS. don't think its true. ask gm. they will tell you.

Thank you for pointing out the obvious.

We were talking about how frequently it cycles.

[Turbocpe]

I've got a question about this. Are you sure it suppose to cycle?

I ask because my '98 Blazer GM shop manual states the following:

"The compressor is a scroll compressor that matches the air conditioning demand by changing the compressor stroke, instead of cycling the compressor clutch. A capacity control valve located in the compressor senses the low side pressure and causes the compressor to adjust to A/C cooling demands. The compressor always runs and the system does not cycle. However, the compressor may cycle if the cooling load is not reduced enough by the capacity control valve."

So, it sounds like the majority of cycles is not normal?

I'd like to know as the compressor on mine always cycles, not rapidly, but does cycle like other past A/C systems that I've owned that I thought was normal.

Thanks.

[BlazerLT]

If it cycles on and off every 3 or so seconds then you are low on refrigerant and compressor oil.

This is really hard on the compressor and will eventually cause a failure.