I recall having that problem a couple years ago when I installed mine, but I don't remember the exact steps I went through to fix it. I did call Garmin on one other issue and mentioned the problem, the tech I spoke with almost seemed offended that I did not call them for help! What I have found with Garmin is they will, and seem to want, to bend over backward to help out in any way. I know the next unit I buy will come from them because of the service I have received.
Rick