1991 300TE 4MATIC: What's this broken wire??
 

Hey there electrical gurus.
Can anyone identify this BROKEN wire? I've been having strange electrical issues lately and wonder if this could be part of the problem.
http://www.i2k.com/~bsmith/wagon/wagon1.jpg

http://www.i2k.com/~bsmith/wagon/wagon3.jpg

Issues:
1. No tach
2. no kickdown
3. ABS light on all of a sudden
(I thought all 3 were related to bad OVP...replaced with new MB OVP and no go.)
4. 4MATIC stopped working
5. rough idle
6. severe loss of fuel efficiency

All happened at the same time. The loss of #1,2,3 has been off and on. sometimes I could start the car again and all is well. Now no luck.

Any help appreciated.

Anyone?

Reconnect it. See what happens?

+ 1

sounds like OVP symptoms, no?

OP said they replaced OVP with a new one

i missed that....darn adult ADD:)

Was the ovp relay replaced with exact replacement? THERE NOT ALL THE SAME

Uhhh... yeah reconnected it and didnt seem to be any different, however it has to be doing something or it wouldnt be there.

OVP is a MB new replacement. Same one as was there originally. (red top)
There is a relay next to the OVP... Anyone know what that is for? I searched the forums and couldnt get an answer.

I thought all those symptoms were related to OVP but new one didnt change anything. good thing it was a cheap part. :)

Here's some info I left out (forgot until after I posted)
1. Early on when the tach was sporadically going in and out, I took it to a local mech and he said it could be one of the round electronic connectors on the drvr side wheel well. At that time, I tapped it with a screwdriver and instantly got it working again. It would work for about a month at a time... then got worse. now nothing. so the AC compressor will not kick on, tach out, kickdown/passing gear not working, and ABS light always on.

So now I have no clue as to what could be causing all those problems all at once except the OVP but I replaced with NEW and still nothing.

** my biggest fear about this is that without the OVP working (if thats the case) then I could be harming the electronics which may be really bad. $$$.

Help!:eek:

What color is the wire under the cover. Where to the ends lead to?

check the tach signal from ezl to round connector thing maybe corroded or loose connectiom, dont remember exactly maybe phillips screw holding wire connector

true, I am afflicted with ADoS... Adult Deficit OHHH Shiney! :)

I Dont know if this pertains to your Model, but some MBZ's had a Tach amplifier on the fender. they go funny no tach

The wire seems to be black. Where it leads...down along the firewall it seems to disappear... I cannot trace it underneath. Maybe goes thru firewall into cab. I''ll dig a little deeper Saturday. It seems to branch from the little tray of wires on top of the engine but I cannot get the cap off it without breaking it.

I do believe I have that, that is if it a black plate-like deal with 3 round cap connectors about the size of a 50cent piece.

I'll take a look more Saturday. I'll actually have a couple hours that I can devote to it!! Thanks again guys for the assistance...and not just the obvious. ;)

I don't have an OE harness on mine as I've got an aftermarket EFI but I *think* that wire goes down to a solenoid on the trans. This model should have an additional solenoid very similar to the kickdown solenoid with pipes that mount it near the bellhousing by the starter. I dont think it could hurt anything being broken so long as it doesnt short to ground while it is active.

you won't believe what (i think) it was...
 

Thanks guys!
Well I checked ground connections, all seem nice and tight.
Put new end connectors on the mystery wire and nothing (noticeably) happened.

Decided that it couldn't hurt to check the brushes on the voltage regulator.
Took it out and they were less than an 1/8" exposed!
Put in a new voltage regulator and now not only does the tach work properly, the jumpy fuel gauge is now working properly, headlights are brighter, dash lights are brighter and starts up MUCH easier than before.

I don't want to be overly optimistic but before whenever I started it up, it would kinda clack a few seconds until the oil got to full pressure. Now it doesnt do that at all. Just purrs. Strange, and I'll watch that one, but seems the voltage regulator may have cured a ton of strange little symptoms.

I know that voltage regulators fix some goofy things...but it's been a few days now since replacing it and seems to have breathed new life into my 317k baby.