I am considering installation of a bulls-i etk1500 dash camera behind the rearview mirror on the inside windsheild. I don't want to thread the power cord along the outside of the pillar. Has anyone attempted to obtain 12v power from the courtesy light on the roof console for radar detector or any other 12v need?
I installed a 3.5" LCD monitor for a backup camera
I probed ever wire I could find where the dome lights were and could only find 12V Constant and 12V Switched when the doors are opened.

I have to turn on the dome light to power up my backup monitor. The monitor does not have a power button. What did I expect for $30?
I rarely need it, so I have not bothered adding a switch.
I hope this helps answer your question.
-Bryan