Anyone know how to test the AC clutch useing this low presure switch? If pics are available please provide. Thanks.

It should be the 'one-wire' sensor in the low pressure side.
Ground the connector to a good ground and see if the compressor cycles 'on' - if so the switch is bad or the pressure is below the set-point of the switch, which could indictate a low charge or the switch being defective.
If it was retrofitted with a 'two-wire' switch sometime in the past*, then jump the two connections and this will provide a ground path and the same conditions as above will apply.

If the above test fails to turn the compressor clutch on, just use a jumper wire** from a 12vdc source - such as the battery term. - to touch the '+' terminal on the compressor clutch contact and see if the clutch pulls-in - if it does the cause is a control circuit not energizing the clutch circuit - check the fuses and switches to see where the power is being 'held-up' prior to getting to the clutch.

Hope this helps;
John

notes:
*= this was a very popular "fix" on some older GM modles when the ground path through the system became "iffy" in later years ...
**= use a fused jumper or Be Very Carefull with this wire that it does not touch anything else or short to the compressor. It is very easy to make a fused test wire by using a "fuse holder" - available in any parts store - and putting an 'aligator' clip on the wire ends to make the necessary contacts for testing circuits.

This is exacly what I was looking for. Thanks so much for your help!