Dealer can't figure out why my new CR9090 won't blow cold air. The compressor won't kick in, gauges show full of freon, first time I got it out of our storage building it was warm air coming out and I had the 01 code showing..dealer ordered high pressure switch and installed it with no change. Today they switched out a controller box from above right side tires behind seat , but from the outside, no luck. Then the tried the atc inside the cab switched with our other 9090 no change. The working combine will click the relay after about 3 seconds but my brand new one will not. I get no codes both on laptop and atc. Dealer left tonight scratching his head. I understand new machines have bugs to work out so no worries or impatience here, just looking for help as to what might be going on. Mechanic said he can get the clutch to engage by hot wiring it...so basically something is not telling it to turn on. Any ideas appreciated.
CR9090 no a/c
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It sounds most likely that it's a faulty electromagnet in the clutch or perhaps it has a poor ground. Sometimes high temperature switches are in the ground circuit for the clutch, that switch could also be bad. I'm not at all familiar with the model.
If the pulley has an enclosed cover to prevent fires, you may have to remove it to see that the clutch isn't actually engaging but the compressor is just not stroking. Most modern compressors have a variable stroke that can automatically be de-stroked when they start at high speed for a soft start when the clutch engages. This keeps compressor output steady regardless of speed. The stroke is determined by internal pressure differentials controlled by a tiny valve in the compressor that can be fouled by a piece of loose material in the system. In that case the compressor will run but just not develop a high and low pressure.
If the pulley has an enclosed cover to prevent fires, you may have to remove it to see that the clutch isn't actually engaging but the compressor is just not stroking. Most modern compressors have a variable stroke that can automatically be de-stroked when they start at high speed for a soft start when the clutch engages. This keeps compressor output steady regardless of speed. The stroke is determined by internal pressure differentials controlled by a tiny valve in the compressor that can be fouled by a piece of loose material in the system. In that case the compressor will run but just not develop a high and low pressure.
Sounds to me if you can hot wire it and the ac blows cold after hot wiring it then it would be a faulty low pressure switch the low pressure switch is a safe guard in the event of loosing Freon it cuts power to the compressor to protect pump from running dry. We have had this happen on two occasions on our 4wd tractors mechanic checks pressures and power to clutch everything seems fine yet it wont send power to clutch replace low pressure switch and bingo.
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At least one of our CXs do this every year at the beginning of the season, no idea why it happens. All I do now is put gauges on it and hotwire the clutch for ten minutes, watch gauges to make sure all is well, plug in clutch again and BINGO! It's good for the season...
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On my 9080 when an AC line failed the display flashed 02 and would try to run the compressor when the display unit was first restarted. Unless a faulty low pressure switch would give different symptoms than that.
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I know the feeling...Funny, I swore the first post said "he CAN'T get the clutch to engage by hot wiring it."
I guess my arms aren't long enough to read my phone anymore !
At least you know what to do in the other situations.
Just an update....ac still not working consistently. It will work right away in the morning for about and hour or so...maybe not that long. Then it shuts compressor off. Dealer has checked connections, it is not sending power to compressor once it kicks off. They did try a high pressure switch. Yesterday they evacuated the system, put 5 pounds in and it worked, but it had been sitting for 2 hours. Made one round and it kicks out. Pressure started to go up on gauges but only to like 220 or 240 when it shuts off. Any ideas cause its frustrating running a new combine without air conditioning everyday. I'll cover all the oil leaks later....Geez, what quality control New Holland has.
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There is a block in the system, how does the low pressure looks?
or the ice sensor in cabin is not working
or the ice sensor in cabin is not working
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I have never worked on a CR but I've diagnosed a dozen Newholland tractor a/c systems. My check list is : Fuse, Clutch, High Pressure Switch, Low Pressure Switch, Thermostat on manual controlled systems or on the Automatic the evaporator sensor for ATC.
You have already check the first three, I would check the the low pressure switch next. The the high and low pressure switches both are normally closed switches, the easiest way to check them is jump wire and see if the system works. The ATC sensor called a freeze switch is a normally open if I'm right, not to sure about it though. For an open circuit switch with only 2 pins just unplug and check if system works. Hope this helps.
Down time on new machinery always is irritating.
You have already check the first three, I would check the the low pressure switch next. The the high and low pressure switches both are normally closed switches, the easiest way to check them is jump wire and see if the system works. The ATC sensor called a freeze switch is a normally open if I'm right, not to sure about it though. For an open circuit switch with only 2 pins just unplug and check if system works. Hope this helps.
Down time on new machinery always is irritating.
So get this. It worked yesterday for 6 hours. If I don't push it and keep all temps low...coolant, low turbo boost, low engine load etc. It stays cold. As soon as I get "dirty air" and run lots of engine load my ac quits and gives me the high pressure code 01
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You still haven't said if you bypassed the low pressure switch. That is where I would go. I have a NH 4WD tractor that intermittently worked. Colder days it would seem to work and then it would brown out on warmer days. Always an intermittent and I blamed everything from expansion valve freezing off to the receiver drier being old to not having quite enough freon. I would take crossroadfarm suggestion and bypass that low press switch. I didn't bother to repair the switch just left it bypassed.
ok thanks, not much need last few days as we had 4 inches of rain in 3 days and now we are back harvesting wheat. When I started at noon it was 49 degrees. its worked past few days. I'll ask my mechanic in the morning. Its been tough to keep track of everything they have tried. Thanks for the input
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