1994 Lexus LS 400 dashboard only lights up when car is warm

When outside temperature is low (0 or under) the dashboard does not light up at start until the car is warmed up enough. This takes a few seconds to a few minutes (sometimes close to 10 minutes, depending on the temperature and the duration the car hasn't been in use). Everything else in the car is okay. My dealer told me the circuitry was corroded and it's not worth the few thousand bucks to replace the dash board module. Does anybody have the same problem? If you do, what have you done to solve it? thank you.