[Monkeydad]

There are usually two ports to check on the AC, a high-pressure side and a low-pressure side.

But 150psi is way too high for either. The high pressure side usually reads about 70-80psi and the low side around 35-40psi. The low side of the one you want to check. You're actually not supposed to open the high pressure side.




When it reads way high, it usually means there is a leak in the line. I went through this with my wife's car last year.

But first, did you read the pressure with the car running and AC on its highest setting? That's the only way to get an accurate reading. If it's reading high, it does not mean there is that much refrigerant in it, that's just an indication of a problem, not the actual pressure.

Test the low pressure side with it running and blowing on high. If it's reading low, add some r134a until the compressor kicks on, should happen just over 30psi.

I am fairly good at car AC repair. Fixed my own before and diagnosed my wife's (was a leaky line and evaporator coil inside the dash...let the pros do that work).