Ok, I must not have hooked up a wire or something, because at night the GPS on the AVIC is so bright I have to turn the screen off to drive.

The kenwood in my truck senses it is nighttime and changes to a night mode. Should the AVIC GPS do this to, or is there another way to auto-dim the GPS?

 

You can give this a try:

https://mustangforums.com/forum/audi...tion-wire.html

I would connect a relay to the dimmer wire because if you dim your dash lights, the voltage may be too low to invoke the dimming feature in the AVIC.