Freon appears fine but compressor will not run. Does anyone know how to test compressor. Is their a fuse.

"...compressor will not run".

Does that mean the clutch turns with the drive belt and the compressor doesn't turn, or that the clutch engages and the drive belt cannot turn the clutch at this point?

How do you know the freon fill is adequate?

Does the second cooling fan start when the a/c is turned on?

There is the magnetic clutch relay in Relay Block No. 5, above the front wheel - driver's side.

There is a pressure switch on the top of the receiver (sight glass).

There is a revolution-detecting sensor on the compressor.

I have identified that I do not have any freon in vehicle. I do not see any visible leak. What is your opinion changing to 134a. Is their problems switching over.

No problems, as long as you have cash.

You cannot see a freon leak unless you put dye in the system. Replace the freon with Freeze12 with compressor lubricant and dye. Keep an eye on the connections and see if you spot dye coming out. It is possible your freon escaped without acutally having a leak. If you don't periodically run your compressor (like in the winter), the seals will dry out and leak freon. You have to run your compressor once in a while to keep the compressor seals lubricated.

The best thing to do is take it to a shop who will leak check it, fix any leaks, evacuate the air out of the system and replace your refrigerant.

I'm cheap so I would try the first experiment.

Check with your Toyota dealer to see whether your car is eligible for the EXPANSION VALVE replacement. IF it is, you will get over $400 worth of a/c work for free.

IF you are not eligible, don't even go near the dealer and look into FREEZE12. www.freeze12.com it works.

Regards.

I have equipment to pull vacuum on system. Is their any other items I will need to do to go to freeze12.

compressor oil - but your charge will just leak out again. You first have to find the leak.