so searching the forum, i found a thread where the navigation screen and the back up camera were inoperable, but didn't see anything else.

in this situation, the battery was replaced by Autozone. after that the navigation screen is blank (back light works). but all other functions appear to be fine. took out and re-installed the navigation disc, but didn't fix anything. checked all the fuses, but all were good. anyone have any other ideas that we can check?