I have a one year old John Deere 3032E. The other day it suddenly lost power, (max rpm 1750) and gave an error code referring to the exhaust cleaning. Being under warranty I called the dealer and he sent a service tech guy up. He took off the access panel for his computer hookup and I could see a large mouse nest. While he was on the phone I blew it all out with compressed air. Under where the nest was happened to be two very large connectors, 40 pin and 80 pin in size with mating wires. Under the largest I could see some chewing but couldn't see how bad. He still felt it was a sensor and said he would pick one up the following Monday. Over the weekend I removed all the panels and did a light pressure wash. I found a second nest in the engine. 4 wires were chewed on, one broken. I made a very careful repair and the tractor is up and running again. I keep the tractor in a clean barn but I know they will be back even though I drive it almost every day. So here is what I am doing. All the wire harnesses I can get at will be wrapped with HONDA ACURA RODENT RAT MICE MOUSE PROOF ELECTRICAL TAPE 4019-2317. The areas where it is designed for a perfect nest I will pack with copper wool, (Chore Girl). Areas where there are single wires that would be impossible to access I will us a long Q-tip and apply Capsaicin cream. This is the same hot stuff that is in the tape. I use it for neuropathy so I know it will work. The tape was 31 bucks on ebay and the cream is about 10 at Walmart and the copper pads were a total of about 20 at the super market. I was in shock to find all this and I will do what ever it takes to keep my tractor in good shape. I know there are many other products but I know my plan will work. I hope this helps anyone who is having a similar problem.