Voltage regulator issues - Page 2 - Mercedes-Benz Forum

Go Back   Mercedes-Benz Forum > Mercedes-Benz Sedan Forums > W124 E,CE,D,TD Class
New User? Register - Forgot Password

BenzWorld.org is the premier Mercedes-Benz Forum on the internet. Registered Users do not see the above ads.
Reply
 
LinkBack Thread Tools Display Modes
Old 10-21-2011, 01:34 PM   #11 (permalink)
Lifetime Premium Member
 
russianwol's Avatar
 
Date registered: Nov 2006
Location: Fairfax, VA
Posts: 441
Lifetime Premium Member
Had similar situation on my 88 W126. The brake indicator was on and battery light was on as well. Turned out the burned diodes in the alternator. If you look at schematics the "blue" thin wire from the alternator goes to the instrument cluster and connects to battery light on one side. There is also a wire from the battery that connects to the same light.

What happens is when the voltage from the battery is greater than the voltage from the alternator, said voltage "pushes through" the blue wire voltage and to the ground thus lighting the lamp. When the alternator voltage is higher it holds the voltage from battery "at bay" and thus the lamp does not light up.

There are supposed to be diodes that prevent the current from jumping from main wire from the alternator to the battery to the blue line. However, if the diodes are busted you'll have a current leak into the blue wire when car is not running. Because of that all kinds of lights can light up if there is current going from blue wire into the instrument cluster because there are no diodes there and they share some connections.

I've written up my findings in http://www.benzworld.org/forums/w126...t-tracing.html

Hopefully all above makes sense.
__________________
Now looking for sewing lessons
Running
1982 W123 240D "Turtle"
Projects
1995 W124 E320 "Rogue", 1991 W126 560SEL "Pegasus", 1992 W140 300SD, 1990 W201 190E 2.6, 1978 C107 450SLC, 1973 R107 450SL, 1999 W140 S500.
Gone but not forgotten:
1988 W126 560SEL - got rear ended, 1993 W124 500E - parted.
Parts:Ebay Store | In DC Area? Rent my tools, time, trailer or knowledge!
russianwol is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 10-24-2011, 01:45 AM   #12 (permalink)
BenzWorld Member
 
RuffStuff's Avatar
 
Date registered: Jun 2004
Vehicle: '82 W123 300D, '93 W124 300D, '01 W220 320 cdi
Location: Portugal
Posts: 120
Send a message via MSN to RuffStuff
Quote:
Originally Posted by augapfel View Post
.....Part number???
The part is aftermarket and i don't think Mercedes sells that part. Il try to find out the brand and I'll get back to you.

@ larrypayne - I don't know why the wear is unequal but it is consistent with what happens also on our W123 300D.

@ Zeitgeist - Thanks... ridiculously big for this job though.

@ russianwol - Thanks for the extra info. Fortunately, the diodes seem ok. What a dream of a car that 126 of yours btw!
RuffStuff is offline   Reply With Quote
Reply

  Mercedes-Benz Forum > Mercedes-Benz Sedan Forums > W124 E,CE,D,TD Class

Bookmarks



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Topic Author Forum Replies Last Post
Extremely high voltage - alternator or voltage regulator? dsutton01 R/C107 SL/SLC Class 8 03-26-2011 10:49 AM
2006 c230 voltage regulator issues??? 1nickm W203 C-Class 0 04-25-2010 07:07 PM
Voltage Regulator wisetoad General Mercedes-Benz 2 08-14-2009 03:12 PM
What next changed voltage regulator no voltage Wayne4756 W124 E,CE,D,TD Class 5 05-14-2009 08:35 AM
Voltage Regulator rsullivan222 W140 S-Class 8 01-25-2006 01:39 PM


All times are GMT -7. The time now is 02:06 AM.



Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.6.1

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.