[W126 Coupe] Light Issues

[Dan Landiss]

Look again. Yellow wire is low beams. Highs are (from the top of the 
page) BK/VI, WT, WT, WT/BK and WT/BU for the instrument cluster high 
beam indicator.

"Right" and "left" are to be interpreted as if you are facing the 
direction of forward travel, i.e. left = driver in the US.

All the diagrams, connector locations, interpretation of wire sizes, etc 
are in the service manual. It fills two CDs, and copies are floating 
around here and there. Someone on the list was selling the copies for a 
while but I don't know if he still does so. I'm on my way out the door 
but will be back about 6pm if you have more questions.

on 2/28/2011 12:23 PM calvin young wrote:

> *_See my comments in the notes below.  the car failed inspection and I 

> want to get this done. Otherwise, I would consider this an interesting 

> problem;_*

> Cal

> > Whoa!  OK, you're giving some additional information here.  Looks 

> like someone has been "working" on this electrical system before... 

> some lights working, some poorly and some not at all..... and on both 

> sides.   " The voltage on the passenger side of the car are different 

> than those on the driver's side. "  How can the voltage be 

> "different"? I have learned that things in life often do not follow 

> the script.

> I have learned Adding a new ground to a light shouldn't cause the 

> light to not work (unless now you have no ground at all).  Same 

> comment.  I thought it very strange.  That is why I requested a wiring 

> diagram.  Too bad the auto schematic does not give voltages as a 

> regular electronic schematic would.  Something else is happening 

> here.  Could be indeed that you need a complete new (european) light 

> switch. Just might need a new switch.

>

> > -Bellamy

> >

> >

> > You can send me any questions and I will try to answer them. The wire

> > colors should be abbreviated, next to each wire. The numbers are an

> > approximate millimeter diameter. NOW THAT IS INFO THAT EXPLAINS 

> MUCH. IN ELECTRONIC DIAGRAMS THEY WOULD BE VOLTAGES.  SOMETIMES YOU 

> CAN KNOW TOO MUCH AND WIND UP WITH THE WRONG ANSWER AND NOT ASK THE 

> RIGHT QUESTION.  "C" numbers are connectors. IS THERE SOMETHING THAT 

> SHOWS WHERE THESE CONNECTORS ARE ACTUALLY LOCATED?  PAGE 208 FOR EXAMPLE.

> FROM THE DIAGRAM I CAN ALSO SEE THAT THE YELLOW IS ALSO HOT FOR THE 

> HIGH BEAMS, AND HAS A HIGHER AMPERAGE.

> IS THE RIGHT HAND BEADLIGHT THE PASSENGER SIDE?

>

> >

> > Note that the right and left sides have separate fuses and separate

> > grounds. The ground wires are almost always brown (GOT THAT) on MBZ. 

> If you

> > happened to ground a white wire (like you might in household circuits)

> > you blew a fuse.  I FIGURED THAT WHITE WAS HOT.

> >

> > The wiring diagram style used in auto manuals is a hybrid between

> > conventional electronic schematics and pictorial assembly drawings. 

> It's

> > not too bad after you get used to it.

> > ------------------------------

> >

> > Message: 6

> > Date: Mon, 28 Feb 2011 10:27:53 -0600

> > From: Dan Landiss <dan at landiss.com <mailto:dan at landiss.com>>

> > Subject: Re: [W126 Coupe] Thanks for the diagram

> > To: Mercedes Coupes Mailing Lists <mbcoupes at mbcoupes.com 

> <mailto:mbcoupes at mbcoupes.com>>

> > Message-ID: <4D6BCD09.4070601 at landiss.com 

> <mailto:4D6BCD09.4070601 at landiss.com>>

> > Content-Type: text/plain; charset="iso-8859-1"; Format="flowed"

> >

> > It would help to know WHICH voltages are different. In the US wiring

> > scheme, at least:

> >

> > 1) Yellow/black (at the left headlight) and yellow (at the right

> > headlight) should both be near 12 VDC with the low beams on, zero if 

> off.

> >

> > 2) White/black (left) and white (right) should similarly be about 12 

> VDC

> > with the high beams on, zero if off.

> >

> > 3) All brown wires should be near zero no matter what lights are on 

> or off.

> *_I AGREE WITH ALL OF THIS, BUT THIS IS NOT THE CASE.  I WILL CHECK MY 

> INSTRUMENTS, AND REDO THE TESTS TO CONFIRM WHAT IS GOING ON._*

>

> >

> > None of the voltages are ever negative unless the black (negative)

> > voltmeter lead is attached to a reference that is not really 

> grounded --

> > and that could be the cause of the whole kerpuffle.  THIS JUST MIGHT 

> BE THE CASE SINCE CONNECTING BROWN TO GROUND CUTS THE LIGHTS OUT.  AT 

> A MINIMUM, I MIGHT HAVE TO RE RUN THIS GROUND WIRE.

> >

> > on 2/28/2011 10:04 AM Mister McGoo wrote:

> >> Whoa!  OK, you're giving some additional information here.  Looks like

> >> someone has been "working" on this electrical system before... some

> >> lights working, some poorly and some not at all..... and on both

> >> sides.   "/The voltage on the passenger side of the car are different

> >> than those on the driver's side. " / How can the voltage be

> >> "different"?  Adding a new ground to a light shouldn't cause the light

> >> to not work (unless now you have no ground at all).  Something else is

> >> happening here.  Could be indeed that you need a complete new

> >> (european) light switch.

> >> -Bellamy

> >>

> >>

>

>

> The MB Coupes Website!

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> Postings remain property of MB Coupes, L.L.C.


-- 

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