[JRTJH]

There is a procedure to check the Freon charge by using a clamp ammeter on the compressor wiring. The owner's manual/service manual has the instructions on how to perform the test and the test measurement "normal" readings.

I wouldn't assume that it's low on Freon just because it isn't cooling, that may very well be the problem, but there are other issues that could be the cause. No need to replace it only to find out that a thermistor was bad or a "freeze sensor" had slipped out of the cooling coils. Run the troubleshooting logic chart before you spend the money, you may find another problem...

Good Luck.