The latest issue I have and had since I purchased this machine is the a/c not blowing cold. 2768 hrs heat works. When a/ c switch (in the cab) is engaged the compressor would not engage. Clutch side was free no squeals. Went and bought some 134a refrigerant put a couple shots in and the compressor started to engage but still no cold air. My next thought is the electric switch underneath the cab has gone bad
Ok if you had to put refrigerate into it you have a leak if you have gages the low side should be 35 to 45 psi high side should be 240 to 250 with a conventional fan also clean condenser if gas can not cool will not blow cold . If in cable to controller valve to heater core block off the water line to core next back to leak with a sniffer you can find the leak but I do it with compressed air adapter in system with gages hook up 90 to a 110 psi engine off system equalized spray water bottle mix with soap bubbles are a wonderful thing
You need to do a complete vac pull down and make sure the system will hold that.
A lot of people don't have a vacuum pump or a sniffer the vacuum pump will only tell you that you have a leak not were it is his were the spray bottle comes in and once you find the leak and fix it then add two hours to vacuum time harbor freight has a cheap one air operated
You also need to flush system why a part then vacuum for twenty minutes see if it holds 29 for 20 min if so no leaks
Most auto parts store will rent you a vac pump dirt cheap. Not sure about gauges but I think ypu can rent those also
They will only pull it down to 2.5 hg for max you need 7.5 hg
Last time I bought gages was 89.99 so rent or buy up to you but they will work on all 134 systems
Update I heard a whistling sound and fund a hole in the radiator hose.
Correction. Hole in the INTAKE HOSE going tonl the radiator
Why I don't know that the hole is in radiator but if coolant system is low ac will not work condenser cool by fan that is in front of radiator
Next I tested with gauges showed no pressure what so ever. Decided it has to be a leak. Added about 24 Oz of r-134a free on. Compressor kicked on had cold air coming through. Went to open the back engine compartment and a line blew. It was the one to the condenser right where the bend is when the door is shut. I'm thinking there was a small leak before and the high pressure was reading about 150psi when this happened.