1994 W900L AC Theromostat Switch

Data plate claims 5lbs 4ozs. I did have it set to fresh air and I have a new aftermarket air filter installed too. At first, I thought maybe the new filter wasn't letting enough fresh air in to keep the evaporator from freezing and was considering removing it but if it should be set to recirculation instead than that bunks my theory.

 

I'll look again but after searching the first time I didn't see one. Only lines I saw coming out were for the heater core.

 

I'd love to be able to test the switch with a multimeter before hanging a part. However, I do not know the procedure to do such a thing. I'm only assuming it's the thermoswitch because once it's gets too cold it shuts down and the only way I can get the clutch to engage again is to jump the override and A/C thermal switch wires coming off the trinary switch. Otherwise, no power is sent to the compressor clutch after it runs for a while.

 

I do have gauges and I manually cycled the clutch (still freezes up just takes longer). What readings should I be looking for when testing the thermoswitch with a multimeter?

 

I may have read a thread you posted on. I remember seeing you mention that you only run 2.5lbs. How did you come up with that number? Did it freeze when you put the required amount in instead?

Can you tell me what your low/high side pressures are? I may have to charge by pressure versus freon amount.