Hello, I'm not super familiar with red combines, but I am helping a guy out with his. It's a 2166 and the grain loss needle bounces around a lot and it will stick all the way to the right, and then bounce around again. The monitor system seems to work fine doing the tap test on the sensors. That is about all I have tried so far. I looked over the wiring harnesses and it don't look like mice have been to them or any borken wires. Didn't know if there was a common fix for this. Any help would be great. Thanks