[talk about radar detector wiring]
Mine's wired to the power lead for the sunroof motor on my wife's '90 200.
Don't do this!
Problem is that whenever you cycle the sunroof in one direction, the power
surge (drop?) causes the radar detector to cycle. I don't know why, whether
the power actually drops sufficiently, or whether my Passport is finicky,
or what....but it's a PITA.
Find another switched lead. It's not that difficult to run the wiring down
the A-pillar to the fuse box or at least to something under the dash.
One of these days I'll do it myself...
1990 Audi 200T
1988 Volvo 745T