I tried searching for a solution but only found thread relating to flickering or going dark so please pardon me if this has been answered. My navigation system has a couple of green "blocks" on it that have appeared and do not go away. They are only on the display when in navigation mode. Any ideas on a fix?

Thanks in advance!

 

Weak signal from the antenna?

 

Do these colored blocks look like the occasional pixelation you may see from time to time on your LCD television ?
A weak or problem signal can cause this pixelation on new TV's. That shouldn't be a problem for the Nav, since it is getting its info from the disc.

I have had the flickering problem, but no colored image blocks on the screen
Check your head unit connectors (my standard response) This fixed my flickering.
These particular Nav/stereo/SirusXM head units are no longer made and getting a new one is near impossible. Check your dealer and see what he may suggest.
I got a new head unit from the dealer at a much reduced price and the old head unit was a core.
Good Luck