Parts Catalog Accessories Catalog Tech Info Tech Forums
  Search our site:    
 Cart  | Project List | Order Status | Help    

Go Back   PeachParts Mercedes ShopForum > Technical Information and Support > Tech Help

LinkBack Thread Tools Display Modes
Old 12-18-2001, 07:38 PM
Registered User
Join Date: Oct 2000
Location: Havelock NC
Posts: 35
alternator or voltage regulator

The other night I was driving my 1986 560sl and a series of electrical malfunctions occurred; the radio switched off, then the "antilock" light came on followed by the "light out" light illuminating, followed by dimness of all electrical and then the car quit. I took the battery out of the car and had it charged and tested. It tested good and with a full charge had the system checked. With the engine running, the voltage reading off the battery with no electrical load was 12.8 volts. This points to an alternator problem, correct? I was wondering about the voltage regulator, could that be at fault? Any suggestions would surely be appreciated. Thanks. Rob Thomas
Reply With Quote
Old 12-18-2001, 08:00 PM
Registered User
Join Date: Mar 1999
Location: Suwanee, GA, USA
Posts: 4,712
At times, the alternator brushes (inside the regulator), will fail and cause this condition. If you remove the regulator and the contact portion of the alternator armature looks good, I'd just replace the regulator.
Donnie Drummonds
Reply With Quote
Old 12-23-2001, 06:40 PM
Registered User
Join Date: Oct 2000
Location: Havelock NC
Posts: 35
I have had it tested again. It showed 13.6 volts while engine running and I took alternator out of car and had it benched tested and it tested 13.6-13.8. I took the regulator off and the portion of the alternator that the regulator rubs against looks worn but I cannot tell if it is excessive. In summary, it seems to be intermittent. Should I still try the new regulator or a new alternator? Thanks. Rob Thomas
Reply With Quote
Old 12-23-2001, 06:53 PM
mplafleur's Avatar
User Friendly
Join Date: Sep 2001
Location: Lathrup Village, Michigan
Posts: 2,939
Wouldn't the testing of the alternator as good rule it out? The last man holding the stick is the regulator.
Michael LaFleur

'05 E320 CDI - 86,000 miles
'86 300SDL - 360,000 miles
'85 300SD - 150,000 miles (sold)
'89 190D - 120,000 miles (sold)
'85 300SD - 317,000 miles (sold)
'98 ML320 - 270,000 miles (sold)
'75 300D - 170,000 miles (sold)
'83 Harley Davidson FLTC (Broken again) :-(
'61 Plymouth Valiant - 60k mikes
2004 Papillon (Oliver)
2005 Tzitzu (Griffon)
2009 Welsh Corgi (Buba)

Reply With Quote
Old 12-23-2001, 07:10 PM
Registered User
Join Date: Oct 2000
Location: Havelock NC
Posts: 35
I would think so but the one wrench in the entire troubleshooting process was the "bad" test of the alternator in the car. So far, two tests were good, one bad. I will try the regulator. Thanks.
Reply With Quote
Old 12-23-2001, 08:31 PM
engatwork's Avatar
Join Date: May 2000
Location: Soperton, Ga. USA
Posts: 11,246
Rob - what kind of traffic were you in when the problems started. On my E320 my alternator was going out and I only noticed it when I got into heavy traffic with alot of idling around. Same symptoms - radio turned off, etc and I think it went into "limp" mode because of lack of acceleration. When out on the open highway at 55-60 there were no problems.

Replaced the alternator and everything is fine after that.
Reply With Quote
Old 12-23-2001, 11:10 PM
Registered User
Join Date: Oct 2000
Location: Havelock NC
Posts: 35
I was on the highway doing 55. Thanks.
Reply With Quote


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
Thread Thread Starter Forum Replies Last Post
W-126 rear window regulator RG5384 Tech Help 11 07-16-2008 04:40 PM
White Stuff under the Blower motor regulator. Merc1 Tech Help 5 08-13-2005 05:31 PM
Window regulator replacement notes Litton Vintage Mercedes 3 04-11-2004 09:04 PM
W108/M117 fuel regulator query kpb Vintage Mercedes 5 02-15-2004 07:18 AM
94' Regulator removal problem!!!! JOHN07 Tech Help 0 01-26-2004 06:15 PM

All times are GMT -4. The time now is 07:44 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2016, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2011 Pelican Parts - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page