12V source in W126?

"marlinspike" haute in die Tasten:

Pull out the radio. It should have one always-on-power source (for memory serving) and one switched source.

Frank

I should have been more specific. It needs to be up top, near the rear view mirror. I want to hook up a radar detector, and I don't wnat a cable hanging down. Richard

just run your own cable, under the trim and down the front pillar, under the covers of course.

Run it to where? Also, I'm not all that sure how to get underneath the front part of the headliner and then the A-pillar. Doesn't sound too easy. If I could use the power wire for the interior temp sensor I would have no wires running around, it would look clean, and it'd be easy, but does anybody know if it can be done? Richard

Run it off the accessory circuit, easily found behind the radio.

the front trim comes down by removing the sunvisors, and clips and the rear view mirror and anything else attached to it. the A pillar if I remember correctly has a tab with a screw in it at the top back under the side trim. you will need to remove the handle to get the side cover out enough to undo the screw.

The seats, horns, roof, rear defroast and rear lighters are hot in run or start. The glovebox, lights, front lighter are hot in accesory or run.

Look in your fuse box to see which fuse does your (varies by model year) and run yor wire from there.

I wouldn't splice a wire inside the cabin, ever. Half the electrical bugs I fixed on my car were because of this. Stuff that Mercedes wired does last 300K miles. Other wiring mods made, shall we say, after it left the factory did not fare so well and after much fuse blowing and replacing wires are ok now, but run your own wire, please.

Sigh. Dome light. Do a real good clean job. Use lots of insulating tape. when (if would be better) that wire contacts the body - zzzzzzzt - bye bye Mr. fuse.

Dome light is always hot. Richard

I had decided to go with the dome light and just live with using the detector's on/off switch since I didn't feel like running a wire from the glovebox light, but what you say worries me. Do you really think the addtional 225 to 425 mA will blow the fuse? Richard

I doubt that the extra current would blow the fuse, it's the workmanship of the 'aftermarket' splices that causes all the problems.

No, the 225 to 425 mA isn't going to hurt anything, it's the eventual shorting of a wire onto the body that'll blow a fuse. Do a real clean neat job in there.

Oh, of course. I believe there's an official dedicated ground at the back of that cavity too, so it'll be done right. Richard

BTW, you're working with Rusty? Those lemforder oil pans you have for an 85

"working with" is not quite accurate. He sponsors the website a bit.

You'd have to call and ask abtout he oil panns, or email.