Near Intersection of I-35 & I-90 Southern Mn. | Last year, I had a error code concerning the AC come up a few times in my 9770 combine. The local dealer has a program where the combine is left with them over Winter. They have a large storage shed and bring them into their shop as time permits for maintenance. I participated in the program and left a detailed list of the things I was concerned about including the AC error code. I was called in early January to decide upon the debatable items as whether to replace them or let them go for another year. At that time I mentioned the AC codes. The tech was a bit evasive about my questions with it.
The day I was called to pick up my combine and bring it home was an early Summer day and it was very hot. When I got to the storage shed my combine was sitting there idling with the AC on and worked fine. I drove the combine towards home but after a few miles, the AC error code reappeared. I stopped and called the Service Manager and we decided that I should return it to them. A few days later they called and indicated that they had found the problem which was a bad diode in a major wiring harness. Deere's solution was to replace the entire harness which would have been very expensive from a parts and labor standpoint. The local dealer found and replaced a diode within the harness which saved me the cost of the harness. The labor seemed extreme but was probably based on the time which it would have taken to replace the entire harness had that been done. The AC worked fine on the trip home.
Yesterday we decided to dive into some wet corn for the Harvestore. This is high moisture corn around 30%. Yesterday the AC was needed. It worked for a bit but then I got the AC error message again. When this happens, the system shuts the compressor down and shows the error message for a very brief time on the display. The combine and fan continue to operate normally but within a short period of time, there is no cooling effect on the incoming air. The compressor does not restart. Cycling the fan switch causes the error code to reappear almost instantaneously. The error message states something to the effect of "Problem with HVAC system. Check with dealer CC#941". In the upper right hand corner of the display is the code: RCU 243 523744.06. What is confusing to me is that this message only appears for a short time and then the screen returns to normal. If I check the diagnostics for active alarms, the reply is *none. This leads me to believe it is an intermittent short of some type.
I continued to combine but had to quit for a while due to impending weather. What I thought was rain in the distance turned out to be dirt in the air due to high winds. After this passed I went back to harvesting. Since the corn is being blown into a Harvestore silo via a TMR and blower, the grain cart is not always able to keep up ferrying the corn away from me. This means that from time to time I need to wait for the cart. My procedure is to stop before the hopper is completely full and wait. I disengage the head, the separator and return the throttle to idle while waiting. If I then cycle the fan switch, the compressor runs and produces cold air. It appears to be operating properly at that time. When the cart is near, I proceed to begin to harvest again by engaging, the separator, head and go to high idle. At that point very predictably the error message appears and soon the air is uncooled.
A Deere tech is coming out today to investigate again. The RCU error code seems to indicate that the compressor is engaged when it shouldn't be. My thinking is that the AC system is able to produce the cold air but is being told that the compressor is running when it shouldn't be. I'm rained out today. My fear is that it will work and test out just fine today.
Any ideas or similar experience??
Edited by tedbear 9/18/2018 08:36
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Air Conditioner code on Deere 9770 combine
