Do you have a lift-out panel on the top of the dash? If not, you'll have to access the monitor from underneath. You might start with a can of contact cleaner. Remove each connection, spray, and re-connect. That might solve the problem. If not, remove monitor, (mounting methods vary) and bench test it. An LED color 7" flatscreen monitor can be had for under $50.
Bob & Donna
'98 Gulf Stream Sun Voyager DP being pushed by a '00 Beetle TDI