I would like to hard wire my Valentine 1 radar detector into the wiring of my 1987 300E. I would like to tap into the wiring up by the headliner/rear view mirror (e.g., the wiring for the sunroof or dome/map/seatbelt reminder lights). Has anyone done this who could give me info re: how to access the wiring up there and what wires to use (I know I need to tap into one ground and one wire that is hot when the ignition is turned on). Thanks for any help.

i have a w202 and a hard wired the v1 to the light inside the compartment box (that's a wire that's not hot when the ignition is off) make sure you tap it BEFORE the compartment switch (which makes the light turn ON when the compartment is open (and i think is the only way to do it since the switch is ON the light fixture itself)

but then you would have to run a wire all the way up from the A-pillar via the headliners to the rearview mirrors (i just have mine sitting low on the windshield rite above the the dash...mounting it higher dun help much IMO)

I hard wired a passport in at the sun roof controls. I just used some wire I had lying around, not very heavy, to get it apart I had to sort of force it. Just have to look athow. I found a ground terminal for the ground and using a volt meter found terminal which was hot with ignition on and off with the key off.
93 300 SD