Got my D3 installed, however the display is too bright at night, seems like the D3 should know when the lights are on?

if you used a standard wiring harness adaptor, the dimmer wont work.

fords send a digital signal to their head units, which most aftermarket stereos dont understand.

you need to tap the dimmer wire into the headlight on wire in your car. search the forum, there was one guy on the mustang owners forum who did a very good write up on installing the d3 with a backup cam, complete with pics of everything.