I have been having trouble from my AC. Sometimes the compressor cycles like it should(coming on and staying on), and sometimes it cycles fast. I hooked up a guage to the low pressure side a couple of hours ago and it said 35 while the compressor was staying on. It seems like in the hottest part of the day is when it decides to fast cycle and not blow cold. What could be causing it to sometimes work and sometimes not? Thanks in advance for replies!!! If anyone needs to know its a 99 ram 1500 4x4 5.2

 

when they cycle fast it usually means a low charge , low side should be around 25-30 and the high side in the 150 -200 range . but it all depends on the vehicle. normally the low side climbs when the compressor is off and drops down to the 30 range when it cycles on. when its real hot out it has to work harder to cool the cab and since its most likeley low its gonna try and cycle faster.

 

Low freon will make it cycle fast or high or low side pressures out of range will do the same

 

where is the port located that you put the recharge kit on?

 

on the passenger side up close to the firewall. It will have a black cap on it with a L on it.

 

so not the line along the fender but the line closest to the firewall rite?

 

the line closest to the firewall on mine doesnt even have a cap on it. The other line has a black cap rite near the grille and fender but the cap isnt marked with and L or and H. Do i need to put a cap on the other lien also I'm assuming

 

The refill kit will only fit on the low pressure side port. The ports are different sizes.

 

so i tried this tonight and I noticed the top line was not cold at all. If anything it seemed warm. I emptied the entire can and the bottom line was cool but not cold. AC is still warm and didnt notice to be any different then vent air when not using AC. Any ideas? so I try another can or what is it?

 

Was the compressor running?