Loose wire found in engine bay - PeachParts Mercedes-Benz Forum

Jeremy5848 · #1 08-29-2006, 08:40 PM

While doing some 300D engine bay cleaning, I removed the windshield washer reservoir (it was dirty inside as well as outside -- I guess the soot gets everywhere) and cleaned the chassis all around it.

While so doing, a loose wire flopped out from somewhere. It is actually two wires, one brown and one blue, in a piece of black tubing. The tubing comes out of the wire bundle that runs down the left (driver's side) fender and splits off to various places like the headlights, a/c compressor, windshield washer pump, etc. The two wires are not heavy gauge -- 20 or 18 at the most. They appear to have broken off of something long ago but as far as I know, everything works.

I know that wiring harnesses sometimes have wires for options that aren't in every car, but those wires are usually taped off. These look like they had been used at one time. The brown wire was sticking out of the tubing and had some exposed conductor while the blue wire was back in the tubing until I pulled it out for the picture.

The wires are long enough to reach anywhere on the left front part of the car. They don't belong to the horn or the lights or the auxiliary fan. I haven't looked at the schematic and can't imagine what purpose they might have served. Any ideas?

westkill · #2 08-29-2006, 08:55 PM

Just a guess but didn't the gas engine versions have a outside temp gauge. Could that be for the sensor???

Jeremy5848 · #3 08-29-2006, 09:23 PM

Excellent guess. Definitely no place in my dash for a temp gauge (I'd love to have one, though). I'll visit our neighbors in the gas forum, see what they say.

[Edit] ...the gassers say "no W123 ever had that option..."

#4 08-29-2006, 10:22 PM

Is your AC compressor connected? According to my wiring diagram, it should have a brown wire and a blue/white wire to the clutch.

Jeremy5848 · #5 08-29-2006, 10:40 PM

Thanks, Craig, I meant to put that in the list in my first post. Yes, the compressor lives in that neighborhood, but its wires are OK (and it even works

). And the compressor's clutch has way heavier wires than my "found" wires. They would not operate much more than a couple of small lightbulbs.

#6 08-29-2006, 10:52 PM

I give up, maybe a hood switch for an alarm system. I can't think of anything else in that area either.

Jeremy5848 · #7 08-29-2006, 11:10 PM

Interesting. Never thought of that. This is definitely a factory wire; was there a factory alarm option?

[edit] Did a search. Found a couple of threads. It does appear that there was a factory alarm option on the 1985 300D.

#8 08-29-2006, 11:35 PM

Quote:

Originally Posted by Jeremy5848

Interesting. Never thought of that. This is definitely a factory wire; was there a factory alarm option?

[edit] Did a search. Found a couple of threads. It does appear that there was a factory alarm option on the 1985 300D.

Interesting, I didn't know there was an alarm option on the 300D. I removed some old switches and wiring from the hood and trunk of my 82, but they appeared to be after-market.

Lycoming-8 · #9 08-30-2006, 12:39 AM

Our 85 300D parts car has a factory alarm system. Also has the cable to release the trunk latch under the rear seat. The 85's were really different in many ways. It will be a few days before I can look on the parts car, but will check to see if it has the wires in question.