2004 santa fe 130k miles 3.5L. I have a puzzling Ac issue. So the ac blows cold and after 5 minutes blows warm. Did a test today and this was the sequence of events. Put my 134a gauges on.
Started it up. Ac full max set to 62 degrees. Blew cold. Pressures looked good. Fan on inside of motor spinning. Hit gas ran up to 1800 rpm and held for a minute. Still cold and pressures good.
Car warmed up, cooling fan on outside of motor started. Around this time was 5 minutes, compressor stopped spinning, blowing warm inside, both cooling fans still running. Turned ac on off, turned car on off. Still no compressor. Now when the car cools off it will work, for 5 minutes. So what switch or sensor do I need? Thanks for the help
Define “good pressures”
Also, what is the ambient temp where you are? It’s 60ish degrees here right now, so I wouldn’t expect an a/c compressor to stay engaged for long on my rig. (admittedly, I am not entirely sure how a Hynduai SanteFe is set up.)
Florida it was over 85 degrees that day. Gosh I ran the test last week. Friends car. Don’t remember exactly what the pressures were but it was in the normal range that I see when I play with cars. Never got low enough to trip the low pressure switch. I wanna say the high side might have gotten a up around 200+ at idle. low side depending on rpm 25-50ish
The AC system has an engine coolant temperature sensor for the AC control module.
This is in case that the engine should start to overheat, the sensor sends a signal AC control module, and module shuts off the compressor to prevent the engine from overheating.
So it might be that this sensor has failed where it’s telling the AC module that engine is starting to overheat when it’s actually not.
This may be why the compressor shuts off after the engine is run for five minutes, and won’t operate again until after engine cools down.
Tester
Tester, Thank you so much. That got me in the right spot. Turns out the temp sensor was doing its job. It was low on coolant. When I had it at the house and the ac stopped by the time I got back in the car the temp gauge read normal from the big fan running for a bit. According to her the ac has been this way for a month. Now here drive to work is literally 5 minutes. Its been about a week since I had it. When I read your post I asked her if the temp was ok. She said yes. I said start it in the parking lot and let it sit and see what happens. It hit the red line before coming down a bit. I put some coolant in it and found a drip. Every ten seconds out of the lower radiator hose at the water pump with it running. Oh and while we were chatting for half an hour the windows frosted up from how cold it got in the car! Problemo solved! Just got to put on a hose in the next couple days
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I’d wipe that area down bone dry and make sure that it’s the hose. Quite often, the water pump will develop a leak out its weep hole, and that will dribble down the easiest path onto the hose.
Thanks for the tip. I wiped it and watched it with a light and a mirror but will double check it. Going to do the hose sometime this weekend.