Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help




Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Diesel Discussion

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 06-29-2010, 10:09 PM
VW1300's Avatar
Registered User
 
Join Date: Feb 2007
Location: Houston, TX
Posts: 463
Turn signals and tach died - coincidence?

Within the last week, the tach on my '85 300D stopped working correctly, and now the turn signal relay seems to be on its way out. Sometimes the signals don't work, sometimes they do. Is this a great coincidence, or is there something I don't know that may tie the two things together?

More info: the turn signals were clicking rather quietly lately, it is conceivable the relay is dying. The tach was working great up until one day it started giving a needle position that was directly related to the position of the accelerator rather than actual engine rpms. For example, if I'm going down the highway - if it works at all - it will show about 800 rpm. If I let my foot off, it drops to zero. Foot back on, back up to 800 rpms. Even more info: about two weeks prior, I had it in the shop for A/C work (don't get me started on that subject), but the mechanic is one of the best in Houston, if he messed something up it was probably not due to incompetence or ignorance. Oh yeah, the tach thing started on the day that the A/C stopped working, presumably due to lost R12 pressure from a leaky compressor. Long story.

Any ideas? I'd like to get my signals working, even though no one else in Houston uses them.

thanks,
__________________
Charlie

---------------------------
'66 VW 1300 96K miles
'97 E300D 239K miles
'85 300D 203K miles (sold Sep 2012)


Reply With Quote
  #2  
Old 06-29-2010, 11:42 PM
Craig
Guest
 
Posts: n/a
Check the fuses; on my 82 the tach, turn signals, and brake lights are on the same fuse. Even if it looks OK, try replacing it.
Reply With Quote
  #3  
Old 06-30-2010, 09:51 AM
VW1300's Avatar
Registered User
 
Join Date: Feb 2007
Location: Houston, TX
Posts: 463
Well the turn signals worked on the way to work this morning, but still no tach or A/C.

OK, cleaned up the fuses just now. From the Haynes manual, it appears that the turn signal relay is on fuse 2. Hard to say, it doesn't give a diagram for '85 US models. After I cleaned up the fuse, I put it back in and it arced a tiny bit when it touched the contacts. ??? The clock is also on fuse 2, I guess that's where the current is going.

The weird thing is that after the fuse cleanup I tried the A/C and it started to work again. The tach needle moves around but not in direct relation to engine revs. Turn signals seem to work a little faster, though that could be wishful thinking.

Question - until the signals start to fail again, I'll have to let that remain a mystery, but what's the next step to diagnose the tach problem?

thanks,
__________________
Charlie

---------------------------
'66 VW 1300 96K miles
'97 E300D 239K miles
'85 300D 203K miles (sold Sep 2012)


Reply With Quote
  #4  
Old 06-30-2010, 10:00 AM
TX76513's Avatar
Platinum Member
 
Join Date: Apr 2003
Location: Brandon, Mississippi
Posts: 5,203
I am going to step out here a bet you a donut That it's your ignition switch. If this happens again - with the engine running wiggle your key gently left to right if ac fans, tach, signals start working it's the contacts on your ignition switch (not the tumbler).

.02
__________________
BENZ THERE DONE THAThttp://www.peachparts.com/shopforum/...c/progress.gif
15 VW Passat TDI
00 E420
98 E300 DT
97 E420 Donor Car - NEED PARTS? PM ME!
97 S500
97 E300D
86 Holden Jackaroo Turbo D
86 300SDL
(o\|/o)
Reply With Quote
Reply

Bookmarks

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 On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -4. The time now is 08:29 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page