Hello all,

I'm having a bit of trouble with my 1993 full size blazer. I did a complete a/c system install. New compressor, accumulator, (stubborn) evaporator, and all new lines. At first i couldn't get the clutch to come on. I jumped the ac switch to see if i can get it to come on. That seems to work so i replaced the a/c switch. After replacing the a/c switch it still didn't come on until i jumped the switch again and then introduced a partial charge of 134a. After hooking up the switch the compressor clutch engaged, but after running for a while it never cycled off and on. This is after a complete charge of 134a. The air blows cool from the vents but not cold. The low pressure side of the system starts to sweat. Other things that are happening is that the air from the vents gets cooler as you rev up the engine. So i decided to go for a little ride. Stopping every other block or listening to see if the clutch of the compressor ever disengaged but no luck. Also i would like to add that once my friend hooked it up with a/c gauges it read low side 60 and high side 245. Oh i did vacuum down the system for an hour and locked it in for another so there isn't any leaks. Pls is someone can enlighten me on what should i do.

 

I checked my AC reference book, and your readings are high on the low side. Should be running about 35psi. You high side is okay at 245, and can go up as high as 300 if it's really hot. Your oil capacity is 3 ounces, and your refrigerant is 3 pounds. First off I assume you put oil into the compressor, and accumulator, and just to verify the freon wasn't over charged. If all these things are good we'll need to look further.

 

I forgot to add, you can unplug the blower motor while running the system, and it should cycle. If not I would replace to pressure switch for the clutch. They sometimes can run without cycling for a while if thing are really hot outside, but you should be getting cold air while running down the road.

 

Thanks for the info after getting frustrated with the ac I opt to take it to a professional. He revaccumed down the system and said the system had enough oil and added dye to check for leaks. After that he added freon and e erything checks out but ac still doesn't cycle and the proformance isn't that good either but better than before. On the highway it gets pretty cool. The accumalotor sweats but not that much even on a humid day. I would have to get a thermometer to see exactly what my dash temps are. Maybe I'm asking for to much lol.