1987 Park Ave. Compressor Clutch

I have inherited Mom's old car and the A/C is not working. Thought I would check the freon today, because the compressor clutch is not engaging. The guage shows it does not need freon. What can I check? The compressor is down beow the motor and I can just barely see it, but I can see it well enough to know that the clutch is not engaging.
Thank you for any help.
I have since tried something and have another question : I have shorted the clutch recycling switch out, (that is mounted on the accumlator), and the compressor clutch has kicked in, but the thing is still blowing hot air. What does this mean?

I have inherited Mom's old car and the A/C is not working. Thought I would check the freon today, because the compressor clutch is not engaging. The guage shows it does not need freon. What can I check? The compressor is down beow the motor and I can just barely see it, but I can see it well enough to know that the clutch is not engaging.
Thank you for any help.
I have since tried something and have another question : I have shorted the clutch recycling switch out, (that is mounted on the accumlator), and the compressor clutch has kicked in, but the thing is still blowing hot air. What does this mean?The AC system is low on refrigerant and be sure to not run the compressor too long with the pressure switch "shorted out"; because it needs refrigerant to circulate the oil in the system! You have an R12 system which was banned in 1996 and it is very expensive & hard to find a replacement Freon. There is no easy fix here, you need to take it to a professional AC shop for advice & diagnosis!