cbowden

The AC system was not blowing cold air so I checked to see if the compressor was coming on. It was not. I got a bottle of R-134A, the one with the hose, fitting, and guage. The gauge said that the pressure was around 110 psi, but the compressor was not running so this was still a static pressure. As a test, I jumped the cycle switch (pressure switch) and the compressor turned on. I got in the truck and the AC was blowing cold. So, I assumed, which is probably not the best idea, that the switch was bad. I went and paid 100 bucks to have the system evacuated and a new switch installed. Now, the compressor runs for 5 seconds, stops for 10. It continues this cycle over and over. This truck is a 2003 Silverado 2500 with about 40,000 miles on it. Does anybody have any suggestions? What happens if a system is overfilled with refrigerant? Is there a switch that will shut the compressor off prematurely?

viperjuice

yeah dude, pressure switch which is in the reciever dryer. with the system low or high it'll cycle on and off..

tjrogers

I just had my 2003 Chevy HD2500 4x4 Duramax/Allison (with approximately 75,000 miles) in the shop last week for the same problem. I purchased the same type of R134A and it showed that I had too high of pressure. I took it in to the dealership under extended warranty and they replaced the AC Compressor. This did not provide any results - AC blew 77 degrees at the Vent on a 96 degree day. My wifes suburban blew 54 degrees at the same time, so I knew that the problem wasn't fixed. I took the truck back into dealership the next day and the replaced the Accumulator. Now my truck is blowing colder than the ever. 46 degrees on a 96 degree day.