Hello to our forum gurus. I’m retired from almost 25 years Military service. So now I’m trying to serve more great Americans in another way. Our senior citizens that have worked hard paying into the system (SS) and getting very little in return at retirement. I’m try to get this elderly ladies 2015 SD ac working. The problem began with the ac blowing cold while driven but blows hot when sitting still. In observing the engine compartment I noticed it appeared the cooling fan had low rpm. When I pressed a broom against the fan it easily stopped. So 1st I replaced the weak fan clutch. Hot ac still existed. I hooked up a set of gauges but noticed when I removed the low pressure cap, it was pressured up. The pressure on the gauges were as follows: Low side 20psi and high side would go up to 375 clutch kick out and cycle back on at 200psi. The system would not take any refrigerant. So 2nd I replaced the leaking schrader valve and vacuumed the system. Under a vacuum the system would only take 6oz of refrigerant. So I assumed a blockage. So 3rd I replaced the expansion valve, vacuumed and attempted recharge. Again I could only get it to take 6oz into a vacuum. So 4th I replaced the filter/drier and condenser. Vacuumed the system. Attempted a recharge. It accepted only 6 oz only. So 5th I replaced with a new compressor. Vacuumed and attempted a recharge and still accepted only 6 oz. I decided to try a can/hose combination and it took another 6 oz with the engine running but I started smelling a hot clutch so I shut down the engine. The the high side continues to cycle to 375 and off and on with no cooling. Does anybody have any idea what is going wrong?

 

If the fan isn't drawing enough air across the condenser then you will get those high pressures. Take a water hose and wet the condenser and see if the pressures drop and you can get it to take gas. Sounds like the fan may have issues. I've seen similar but it was a wiring harness issue at the front of the engine going to the fan connector. One wire was broken. Fan wouldn't speed up. It also didn't throw any codes for the damaged wiring.