exi

Previous pre-facelift S550 coupe, current post-facelift S63 coupe, both left-hand drive.

In the S550, I recall there being a switched circuit in the driver's side dash fuse compartment which I tapped to power a radar detector.

Either my memory is playing tricks on me, or I'm just stupid, but it seems that in this facelifted S63, all the driver's side dash circuits are always on / not switched, and the passenger footwell fuse compartment doesn't have a readily available ground.

Running the cable at the headliner and A-pillar is easy, but, suggestions on an alternative approach? Don't want a third-party radar mirror.

Mounting a V1 flat is also iffy with the angles of the glass at the cutout to the right of the RVM, but, have to power it first...

exi

Looks like my only two real options are mirror tapping - which I've not dug into yet - or tapping into the cigarette lighter harness behind the ashtray unit, which I've also not looked into as far as what is what back there. Appreciate any guidance.

streborx

The 12V accessory sockets are (of course) fused, but if your S550 is similar to my G550, the fuses are under the rear passenger side seat, which is hardly convenient. Finding a switched power fuse circuit is complicated by delayed shutoff on some of them, and the delay timing never starts if the doors are open. On my BMW, I had to fabricate a small fuse block plug-in with an LED that I could see through the window. I'd plug it into a circuit I thought might be switched, close the door, and come back 10 minutes later to see if it was still on. Time consuming, but I finally found one.