White Nav Screen - Sometimes

[demian5]

Hi -

I'm a new member and recently picked up a 2002 with nav. It has 3 black dots on the screen, but that's not as much as a concern as the screen is sometimes all white. Other times its OK and works fine. Any ideas on what to check? The radio works fin with the steering wheel controls when the screen is white.

Im very handy with automobiles and will open a module or radio to solder connections or replace components.

Thanks in advance!