Does this green wire in my trunk have anything to do with rear window defogger?

Started by WrightSounds, 26 November 2012, 12:24 PM

WrightSounds

In my trunk is a black wire with the end wrapped around a screw and attached to the upper-inside roof of the trunk (see pic. The silver thing in the photo is a reserve fuel tank which you can read about here: http://forum.w116.org/test-drive/look-at-this-17-gallon-reserve-fuel-tank-in-my-trunk!/ )



When I first saw the wire I followed it until a foot later it ended. Then I found another black wire creeping out from behind the reserve fuel tank which ended up being connected to a green wire which then ends up in the plastic conduit with other wires. They undoubtedly were once connected... the wire casing has writing on it and the two pieces match.





It would seem to me that the wire is just being grounded to the chassis of the car. But what I don't know is what the green wire is? Does it have anything to do with the rear window defogger because that is currently not working and wouldn't that be a peach if this is all that it was  ;D







oversize

Whatever you do, don't cut the blue wire!!!!  LOL!   ;) ;D

PS No idea re you're problem; those wires aren't factory and shouldn't have anything to do with the demister....
1979 6.9 #5541 (Red Bull)
1978 6.9 #4248 (Skye)
1979 6.9 #3686 (Moby Dick)
1978 6.9 #1776 (Dora)
1977 450SEL #7010 white -P
1975 450SEL #8414 gold -P

wbrian63

Far as I can recall, the wires that feed the demister run through the inside of the cabin, not venturing into the trunk.

There's one on the left-hand side of the car (when standing at the rear bumper) and one on the right-hand side. One of the wires connects to chassis ground, and the other is the 12+ source. Also pretty sure the connections are mid-point on the sides of the glass.

They're hidden by the trim panels at the edges of the rear window. You may be able to gently press the trim panel and get a volt meter or test light probe in there to see if you're getting 12v to the glass.

That's where I'd start.
W. Brian Fogarty

'12 S550 (W221)
'76 450SEL 6.9 Euro #521
'02 S55 AMG (W220) - sold
'76 450SEL 6.9 Euro #1164 - parted out

"Bond reflected that good Americans were fine people, and most of them seemed to come from Texas..." Casino Royale, Chapter V

WrightSounds

Thanks so much you guys. I didn't think it had anything do to with the rear window defogger. Just wishful thinking. The previous owner had a new stereo and speakers installed so perhaps it has something to do with that. Anybody think of any reason I SHOULDN'T solder the wire back together?

He also tinted the back window, poorly, and I'm sure he killed the defogger. If so, I'll need a whole new rear window, eh? And one with HOPEFULLY a working defogger?

andyatcrux


I can tell you that that green wire definitely appears to be spliced in to supply power to something that is no longer in your car. Compared it with my electrical. Your trunk light works? Taillights? If so, I would leave it be. I am no expert but I would want to avoid possible power drain or other electrical problems that could occur from attempting to restore something not known to be needed.
1980 Ivory White 300SD. 295,000 miles.

WrightSounds

Hello fellow Portlander! Thanks for the reply.

Now that I think about it I'm pretty sure my trunk light is NOT working. Hmmm. I'll have to take a look into that.
Thanks!