A/C issues. Need Help!

[Reallyitsjp]

2011 shorty with front and rear HVAC. Intermittent blowing cold both front and rear. it will work for a week then go two days blowing hot (not like blowing heat hot) but hot. have swapped ambient air temp and that did improve the air temp when blowing cold, but intermittent issue still persist. Compressor and valves are within 18 months old and are holding proper pressures. no leaks found via dye, vacuum, or pressure tested. Possible clutch magnet going out? I am lost.

 

[99WhiteC5Coupe]

2011 shorty with front and rear HVAC. Intermittent blowing cold both front and rear. it will work for a week then go two days blowing hot (not like blowing heat hot) but hot. have swapped ambient air temp and that did improve the air temp when blowing cold, but intermittent issue still persist. Compressor and valves are within 18 months old and are holding proper pressures. no leaks found via dye, vacuum, or pressure tested. Possible clutch magnet going out? I am lost.

With the engine cold - have a helper start the engine but ensure the a/c is off.

You should be standing at the front side of the vehicle with the hood open.

Have the helper turn on the a/c. Does the second (or both) radiator cooling fans immediately turn on?

If not, you may have an issue with the cooling fan(s) - which would not allow the a/c to operate properly (as it wouldn’t cool the condenser).

 

[JamaicaJoe]

I had a problem with AC on my 01 his weekend and it blew very warm. I looked and the compressor was spinning OK. Yesterday I went to check pressure (on low side) and found the clutch cycling. As a result, the low side pressure fluctuating below 20 LBs and then up to 40 LBs. The higher readings were probably when the clutch released.

I put about 10oz of R134a into system and was able to get the clutch to stay on and produce about 46 F at the dashboard outlets. I probably need about another 10 oz because the ambient suction pressure was not attaining above 30 to 50 LBs.

I think the reason the compressor was running when I first looked was that the ambient temperature/gas pressure was high enough that the low pressure switch was not activated. Only after sitting over night was it evident of a low charge. I do see UV tracer on a hose from the dryer can. So probably that hose is shot.

 

[Reallyitsjp]

I figured it out! Through diagnosing determined clutch was being commanded but not engaging properly. Ordered a clutch. Went through double checking and found clutch relay under hood had debris (a bug and some sort of nest) in the pins. Sprayed connector cleaner and reinstalled. Spent 8 hours in the truck today. Worked flawless. So we will see! Thanks all for the input!