I think I've narrowed down my 2 problems ,radiator fan always running and excessive AC compressor cycling. It seems that I have 2 AC high pressure switches installed in the rear of the compressor (GM makes a red high pressure switch which is physically identical and interchangable with the correct white low pressure switch-be careful). I got new, correct ones but I'm not sure of which switch goes where and which wire goes to which switch.

There is a red high pressure switch with a mushroom shaped "female" electrical connector. There is also a white low pressure switch with a "male" electrical connector. The two wires have corresponding connectors so they can't be crossed up (unless the aftermarket replacement switches are "backwards").

Is figure 18.5 on page 127 of the HAYNES manual for the V5 compressor correct. Are the High and Low switches correctly labeled? I want to be absolutly sure before I go switching switches and wires on my compressor. I could very well blow everything up if I'm wrong.

Yes, it is correct. High side cut switch (red one) takes the small mushroom connector. In it's mounted position will be on the side which faces the front of the car.

Every cycling problem I've had was due to low system charge.

Top the system off

My initial assumption on the cycling problem was low system pressure. But everytime I check it (I have a guage) it appears to be at a typical level (It's been a while but I think it was about 75 PSI-ambient/AC not running). But until I need to get the hardware issue 100% straight before I can speculate as to problems from the freon level.

Tom,

You might want to look for a crimped or otherwise restricted return liquid line that may be generating a high pressure situation at the compressure head. Could also have a clogged screen somewhere.

To check pressure readings the a/c needs to be working for about three minutes and idle speed at about 1500. Checking the low pressure side if you have freon 12 should cyle between 25 and 45 on low fan speed. on high speed fan at temperatures above 72 it should not cylce and your low pressure reading should be about 28 to 32. The colder the outside temperature is the more often it will cyle at any fan speed. If it is cycling beteween 25 and 45, then the high pressure switch is probably not your problem.

What motor is this on? I didn't think anything but 87-88 4 cyl had V5 in Fiero.

DelcoAir V5 comrpessor is variable displacement. It should not cycle at all according to GM documents I have. There is a pressure valve in the compressor that adjusts displacement to accomodate system load.

Also you must fully load the system so the compressor is at max displacement or your pressure readings won't mean anything. There's whole big chart for this compressor in the shop books and ALLdata.

The V5 that is pictured in Haynes is exactly what is on my 88 Formula V-6 and I am certain it is original. As for the accumulator, I guess I'll go ahead and install the new one $$ since I'm keeping the car for the long haul.