Interesting about changing the Theme.... I haven't tried that. So far I have found that if I start the truck when it is dark outside, the Navigation comes up. But if it is already bright outside no Nav. I was going to try covering the daylight sensor this afternoon to see if it really makes a difference. I have also tried "resetting the can bus" Not really sure what that means but I read in a TRX forum when I was having heads up display issues.... that if you turn on the ignition...but not the engine then shut it off and then open the door, close the door and wait for the dash to go completely blank. and repeat that 3 times, it will reset the can bus. That didn't really do anything for this problem, it probably didn't fix my HUD either..... but that somehow stopped being a problem.