Just replaced the mk4 nav unit with another, and the screen has become dim. Its like its faded, and sort of the contrast white balance has changed, as its hard to see the writing in some angles.

Its definately not the screen, as when i put another unit in, the screen is back to normal. Any suggestions anyone? Tried downgrade and upgrade already. Also tried a different drive, but i doubt that has anything to do with it.
I really didnt think the mk4 unit had much to say to screen regarding brightness/contrast/white balance.