Auto Air Conditioning & Heater Repair: Air conditioning not working, r 134a, olds aurora

Question
Olds Aurora 1996
I recently bought this car and the air conditioner worked pretty well, but was cooler if I just manually turned it on instead of using the thermostat. But it did cool acceptably on auto also.
Later, it seemed to have a couple of days that it didn't cool very well...then no cool air at all.
I got some r-134a with a guage and when hooked up the guage shows the pressure as too high. (above 100 psi, maybe 150) So I didn't try to add.
There are two valves in the metal tube going into the fire wall. One is larger and the smaller one is closer to the dash and futher away from the condenser (?) The refrigerant connector fits onto the smaller valve, but I really don't know if it should be on the other one with some adapter or something. I havn't tried to add regrigerant to a car since the R-12 days many many years ago.

I am hoping that there may be some easier option than going to great expense at a repair shop...After all I am driving a ten year old car to start with already. I am competent with a tool box and can replace minor parts at least. I have some helpers available if I need them.

Thanks for your help. You are kind to help people out this way.

Brian


Answer
You need to purchase a manifold set (A/C gages) and attach the hoses to the system in order to see what the high and low pressures are reading before you can do any diagnostics.

Also the compressor MUST be operating in order to get the correct pressure readings.