SL-Class (R129) 1990-2002: SL 280, SL 300, SL 320, SL 500, SL 600, SL 60 AMG

SL/R129: 91' 30sl electrical problem

Thread Tools
 
Search this Thread
 
Rate Thread
 
Old 11-04-2016, 08:18 AM
  #1  
Newbie
Thread Starter
 
mrSL's Avatar
 
Join Date: Apr 2016
Posts: 12
Received 0 Likes on 0 Posts
91' 300sl
91' 30sl electrical problem

Hey,
Recently I noticed a very odd problem in my SL, When I use my turn signals all the dash lights come on, gauges reset, and then return to normal.
I should mention that the battery is brand new and the car has barely driven.
I know that there isn't no magic fix to it, but where should I start my troubleshooting?

Thanks
Old 11-04-2016, 10:59 AM
  #2  
Out Of Control!!

 
Plutoe's Avatar
 
Join Date: Feb 2011
Location: Tampa
Posts: 14,542
Received 1,019 Likes on 947 Posts
1999 E300TD
Start with the relays!!
Old 11-04-2016, 11:13 AM
  #3  
Newbie
Thread Starter
 
mrSL's Avatar
 
Join Date: Apr 2016
Posts: 12
Received 0 Likes on 0 Posts
91' 300sl
Originally Posted by Plutoe
Start with the relays!!
What relays?, what does relays has to do with the problem I described?
Old 11-04-2016, 11:41 AM
  #4  
Out Of Control!!

 
Plutoe's Avatar
 
Join Date: Feb 2011
Location: Tampa
Posts: 14,542
Received 1,019 Likes on 947 Posts
1999 E300TD
You obviously don't know your very old car----get off the couch and search for wiring diagrams and then lift the hood you will find loads of turn\wiper relays---grounds bla bla!!-----remember you asked---"Where to start"
Old 11-04-2016, 11:50 AM
  #5  
Newbie
Thread Starter
 
mrSL's Avatar
 
Join Date: Apr 2016
Posts: 12
Received 0 Likes on 0 Posts
91' 300sl
Originally Posted by Plutoe
You obviously don't know your very old car----get off the couch and search for wiring diagrams and then lift the hood you will find loads of turn\wiper relays---grounds bla bla!!-----remember you asked---"Where to start"
You obviously don't know a lot about any electrical troubleshooting , components and there way of operation , if you would have, you would suspect that a voltage drop/a blown cap at the instrument cluster/ a short and etc.. can cause the problem, I agree with you that poor relay connection can lead to a voltage drop, but it's very unlikely. So in that case I wouldn't mislead others, like you did.
Old 11-04-2016, 04:58 PM
  #6  
Banned
 
bobterry99's Avatar
 
Join Date: Jan 2006
Location: Atlanta, unfortunately
Posts: 1,982
Received 387 Likes on 306 Posts
'09 S600, (2) R129 300SLs, '03 SL500, '03 SL55
Originally Posted by mrSL
...When I use my turn signals all the dash lights come on, gauges reset, and then return to normal.
This is a common problem, and the solution is well-established: remove the cluster from the vehicle, open it up, and replace the 470uF capacitor on the main circuit board. It is by far the largest capacitor on the board, and it is impossible to confuse it with anything else.

Don't waste time even thinking about a relay.
The following users liked this post:
mrSL (11-04-2016)
Old 11-04-2016, 05:48 PM
  #7  
Newbie
Thread Starter
 
mrSL's Avatar
 
Join Date: Apr 2016
Posts: 12
Received 0 Likes on 0 Posts
91' 300sl
Originally Posted by bobterry99
This is a common problem, and the solution is well-established: remove the cluster from the vehicle, open it up, and replace the 470uF capacitor on the main circuit board. It is by far the largest capacitor on the board, and it is impossible to confuse it with anything else.

Don't waste time even thinking about a relay.
Thanks a lot for your reply. From my understanding and research, there are three caps on the cluster pcb, since the unit will be apart already, I figured it will be a good idea to replace all of the three, I couldn't figure out the values of the two additional caps, Are you familiar with their values?
Is there any guide for removing and disassembling the cluster?

Thanks
Old 11-05-2016, 10:55 AM
  #8  
Banned
 
bobterry99's Avatar
 
Join Date: Jan 2006
Location: Atlanta, unfortunately
Posts: 1,982
Received 387 Likes on 306 Posts
'09 S600, (2) R129 300SLs, '03 SL500, '03 SL55
Originally Posted by mrSL
Are you familiar with their values?
They are probably used in a role where any value above a minimum value works fine. I'll guess 100uF will work fine.

Disassembling the cluster is completely intuitive. No special tools are needed. Nothing at all tricky about it that I can remember.

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


You have already rated this thread Rating: Thread Rating: 0 votes,  average.


All times are GMT -4. The time now is 10:32 AM.