2004 Yukon Denali. Already did an evac and recharge, no leaks with the dye we installed. A/c on first start when it’s hot won’t work, compressor kicks on but kicks off. Rev it to 1k, it noticeably kicks on for 15 seconds, cold air, then kicks off, warm air. One truck starts moving it works great ice cold. When I come to a stop it works, not as cold but it’s definitely working. When I get home and put it in park it works. Turn truck off and back on it works. Button turns compressor on and off correctly. It only doesn’t work when it’s hot out and on first start up. I’m so lost lol anyone have this issue before?
A/c weird issue
- Thread starter Tf79
- Start date
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Guess, the system is not full or low pressure switch. What are the pressures when this is happening? Ambient temp when happening?
CraftyCrafts
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Ambient air temperature sensor(s) or maybe the engine temperature sensor
rockola1971
Full Access Member
As OR said....need to know what the ambient temp is outside during a refrigerant pressure test. Need to know that low side pressure when compressor is engaged. The pressure reading when compressor is not engaged is useless. You should be seeing around 45psi or so consistently while compressor is engaged and even higher if you live in high temp areas. The pressures are directly related to the outside air temperature. All readings taken with fan on high, max cooling front and rear A/C.
A proper vac pump down will prove no leaks. I let them sit under vac for hours and then check gauge over atleast an hour period. Most common leaks is the schrader valve cores. Always snug them after hooking up and gauges to the them. Leaking evaporators and the lineset at the rear are also common culprits.
A proper vac pump down will prove no leaks. I let them sit under vac for hours and then check gauge over atleast an hour period. Most common leaks is the schrader valve cores. Always snug them after hooking up and gauges to the them. Leaking evaporators and the lineset at the rear are also common culprits.
ScottyBoy
Full Access Member
Sounds like a faulty fan clutch. Perfect time to convert to Electric Cooling Fans in my opinion.
rockola1971
Full Access Member
Would not the engine overheat if that were the case?
Especially in hot temps, unless on the highway all the time.
rockola1971
Full Access Member
Yup. With the minimal info we have I would say OP is either under or over charged.
Just got the evac and recharge at dealer done. Ambient temp is around 90 when it happens
Dealer did a evac and recharge. Changed the schrader valves. Nothing else wrong in their opinion. Ambient temp is around 90 when it happens. I’ve been watching a bunch of videos trying to learn how this system operates so I can see what else might cause it. No overheating issues, and fan clutch has been swapped. It only happens when I first start the car after work. Overnight it’s fine. You think they didn’t do the evac correctly?
