compressor clutch wont engage.

my AC worked fine last year. The car was parked 4 months for winter with the battery out. in general I am a windows down kinda guy. this year it would not blow cold air. after inspection it appears the ac clutch is not engaging. fuses are OK and relay is in place (but I have no idea if the relay is good)
any tips or tricks or suggestions?

Is it low on freon?

Tom

You can probably swap the relay, or at least listen to it to hear if it is working. If it is not, then it is probably the clutch, or you are low on refrigerant.

my gauge said 25 lbs. on the low side so I don't think I am low on refrigerant.

You may be able to put the climate control in "econ" and it may start even if the refrigerant is low.

25 Lbs is a little low and if your compressor clutch doesn't engage at all that means low Freon.Is your climate control flashing at you where theres a small ZERO to the upper right side of the temp readout?Do this trick,it always works for me after a winter of not using the AC.With your ignition key on,set the AC to 60 degrees and turn key offl,disconnect the positive side for 30 seconds and then reconnect,turn the key to the run/on position without starting,let the AC readout count down from 30 to 0 TWICE.After doing all this the small zero will stop flashing,start the car and everything should work normally.If the Freon is still low,jump the compressor at the drier and charge as needed.I know this doesn't make sense but it has always worked for me and many others,remember these are old cars so I charge my AC to no more than 3/4s full.
Good Luck

I am not sure about any flashing zero?
to be 100% honest this is the first vehicle I ever owned with "climate control" and I hate it.
I like on/off and normal controls etc.
it has taken me too long to figure this out and I hate having to wait to go from 90-60 and vise-versa.

frederickflintstone wrote:

my gauge said 25 lbs. on the low side so I don't think I am low on refrigerant.

Ok, first of all, in a system that has any liquid refrigerant left, 25 lbs pressure indicates the temperature is 30°F. So assuming you want AC because the temperature is actually above freezing, your system is seriously undercharged -- there is nothing left but some residual vapour, and if you did get the compressor to run it would be damaged in short order, since there is nothing left to circulate the lubricating oil.

Other than that, pressure is meaningless when trying to measure the amount of charge in the AC system. And cheap gauges from department store recharge kits are notoriously inaccurate anyway.

For a primer on the B-body AC system, please take a few minutes to read this:
http://buickforums.com/forums/threads/26737-Basic-principles-of-Auto-AC

Given that there is some pressure left in the system, the most likely culprit is a leak at the compressor. Either the shaft seal or the belly seal. The high pressure port is another common issue, particularly if the cap is missing. That said, the leak could be anywhere. I've even seen an evaporator that leaked only when the pressure was high enough to force a bad seam apart, but would hold low pressure or vacuum forever. If the leak is slow enough it may be more economical to recharge the system periodically, although that will lead to premature compressor failure and is not environmentally friendly or legal.

So on closer inspection it was more like 20 psi on the low pressure side.
Given my lack of practical knowledge on AC systems I went ahead and added R134.
She seems fine now. I am hoping I don't have a major leak somewhere.

none of my "newer" vehicles have ever needed recharging, accept my jeep, the AC is non functioning and has not in 8 years I have owned it. I find AC redundant in a vehicle that is mainly driven topless.