Originally Posted by Ghetto Jet
Please bear with me as I try to explain this.
The Compressor clutch engages, the system is fully charged, but it isn't able to maintain cold or even cool air with the fan speed turned up on a hot day in the sun (only blower speeds 3 and 4 are working, a resistor went bad years ago) If you turn the knob to speed 1 or 2 and let the fan stop pushing air for about 5 seconds and then turn back to speed 3 you will get a cold burst of air that lasts only a few seconds. So I know that the car capable of making cold air.
This car has always had working A/C prior to this. I parked it for the winter/spring and it sat for about 6 months. Now I put it back on the road and the first thing I notice is the A/C is behaving oddly. Something else odd the clutch doesn't cycle on/off it just stays on. And when I put it on Max/recirculate the blower speed no longer increases and the air doesn't get cooler. Also, prior to this, with A/C on when I accelerated from a stop I could always feel/hear the compressor engage and bog the motor around 15MPH. That sounds weird, but that is how it has always been. Sitting this car always had mediocre A/C but once you started to accelerate it's as though the clutch went into full engagement around 15mph. It no longer does this and I think this is why the air is weak. Now the air is cooler sitting than it is moving. I swapped fuses and looked around under the hood but I'm not use to working on A/C systems so I'm not sure what to do next.
My three thoughts were the belt tensioner is getting weak and slipping slightly on the compressor, explaining why more rpms seems to weaken the air.
The compressor is not working properly.
There is something electrical causing this.
If this was my car I would just turn this into the winter beater instead of the summer beater. But I have my g/f driving 55 miles a day in it instead of her Wrangler which has no A/C. She can't look like a hot mess when she gets to work.
Have you checked the lines under hood for icing?
Anyway, some common problems I have had were restricted orifice tube and being overcharged. I don't even know if your system uses a tube or not.
FWIW there are do-it-yourself recharge kits that include a pressure gauge on the refrigerant bottle.