jimwood

Well I guess that's one thing they got right with the water pumper.

My Chevy's A/C works real good too.

Body Roll

Hey guys, I know this is an ancient thread- but what fixed Robin's compressor cycling problem in the end? I'm having a similar problem on my '95.

Thanks. Pete

Robin 993DX

I replaced the expansion valve.

Body Roll

Thanks Robin. What led you to that?

Some background on my problem- the compressor cycles on/off every 30 sec or so. When it's running it blows cold. But it seems like it could be much better if the compressor stayed on longer. The low speed condenser fan is working (after I changed the resistor) and the high/low side pressures are ok (225/15psi @ 2k rpm @70F). I'm about to check which switch is causing the compressor to turn off, ie three level pressure switch or evaporator temp sender.

Pete

Robin 993DX

TJ90 was the rennlistner that helped me diagnosed my problem, as when it comes down to A/C I am completely clueless.

MarkD

You might want to remove your CCU and clean the AC switches (small and big snowflake) with electrical contact cleaner (CRC is one mfg). Reltively easy and can also cause short cycling.

Body Roll

I hadn't thought of the switches- maybe I'll give them a shot of contact cleaner. Although the cycling is pretty periodic. I'd expect it to be more random if the switches were to blame.

Pete

MarkD

ahhh. I see.
If the cycling is consistent it won't be the CCU.

JPS

Resurrecting a really old thread here.

So if I summarize correctly, if the compressor is cycling on and off too swiftly:
A) Check there isn't too much or too little pressure on the low side, or ideally both sides with an A/C Manifold
B) Take out the CCU from the dash and clean it throughly (referring to back contacts and fan and all that)
C) Consider expansion valve replacement

Do I have that about right?