Husker:
A couple things, like Roger said, check the switch. If that doesn't do it, check for loose connections, I have been having some problems with my 3520 and in the process of troubleshooting them I have found a couple of plugs that weren't fully locked together (one had come almost completely apart and was giving me an error code relating to the cruise control and MFWD). If all else fails, contact your Dealer, as Deere has been having problems with the clusters and has been replacing them under warranty.
Good Luck,
BILL