Garmin etrex screen too dim to read

I have an older Garmin 12XL and suddenly the screen turned very dark. I tried replacing the batteries and let the GPS rest for a week so the internal lithium battery could re-charge. But that did not work. I just got an email from a friend who had the same problem... it turned out that his unit had changed the screen contrast setting all by its' self.
This may not be the cause of your problem but it's worth trying... go into your "Settings" menu and reset the contrast and see if that cures the problem. Good luck.

Put new batteries in. guess the others were too weak