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 > Diesel Discussion

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 07-22-2010, 12:33 AM
Renntag's Avatar
Registered User
 
Join Date: Jul 2008
Location: Arlington, Va
Posts: 1,289
Power Windows INOP 1986 W126 300SDL

Hello all. I have been working to get my power windows functioning again a few minutes here and there over the last month. Here is what happened along the way. I will update with more pictures over the next few days.


I purchased a 1986 300SDL in early June and had a few items to work out. This has been a little more involved than I had anticipated. The power windows were working perfectly when I started working on the first project.

First order was to get the climate fan to work w/o blowing the fuse. research lead me to installing an external 30 amp fuse. Opening the fuse box to expose the wiring, I found a melted, hacked mess. Unbolting the wires to #16, I decided to bolt them to an auto resetting 30amp breaker. All said and done, it worked.

While in "the mess", I tried to fix a few other wires.





and the fusebox from above.



W = Window relay.
red circle = #16 fuse Climate fan and #c,d power windows.
Green Arrows = phillips screws to open fuse box.

Other than the fuses being unreliable, I love the way this fuse box is modular. Each section detaches from the next. Relay plugs detach from the main body.
This is great for repair and/or upgrades and swaps.

I clearly need a new fuse box assembly. For now I am focused on making this a usable car and may tackle the fusebox project during the winter.

For now, allow me to continue.

The other day a friend was over for one of my 20-30 minute "try to fix the power windows" sessions. He suggested we start all over. This proved wise.

Note in this picture the coloured sections.

Quick over view.
Note upper right corner, Fuse 17 is energized when the key is in Run or on.
If there is power to one side of the fuse and the fuse is good,
power goes to the black/yellow wire that turns on the Window Relay.
With the Relay on, power is sent to Fuses 'c' and 'd' through the Red/Yellow wire.
From there, power moves on to the center console switches.

So we went back to the drawing board and started at fuse 17.

No power. (We may be on to something.... )

Opened up the fuse box and found there wasnt a feed wire to fuse 17 at all. I must have removed it accidentally while dealing with the earlier "mess".
As a test, I bolted the wire that goes from the fused side of #17 (and switches on the relay) to the protected side of the circuit breaker mentioned above.

Ta Da ! power windows. We heard the relay click and we new we were in business.

Carefully studying the wiring diagram gave me a good understanding of how the system worked. I dont know where all the wire are located, but I know how it works. Next will be to find the missing feed wire and then figure out why the moon roof also doesnt work. I am guessing same error on my part early on.

I am still looking for a set of leather seats for my 86 300SDL if anyone has a clean set. Email/PM me.
Attached Thumbnails
Power Windows INOP 1986 W126 300SDL-power-window-wiring_86_126.jpg  
__________________
Parting 1987 300TD

87 300TD (crashed for sale)

83 300TD (need rear wiper assembly dead or alive)
98 E300D *sold
86 300SDL Need W126 Blue door panels.

Last edited by Renntag; 07-22-2010 at 02:07 PM. Reason: continuation. ....
Reply With Quote
  #2  
Old 07-22-2010, 11:11 AM
Diesel911's Avatar
Registered User
 
Join Date: Sep 2007
Location: Long Beach,CA
Posts: 12,304
Quote:
Originally Posted by Renntag View Post
Hello all. I have been working to get my power windows functioning again a few minutes here and there over the last month. Here is what happened along the way. I will update with more pictures over the next few days.


I purchased a 1986 300SDL in early June and had a few items to work out. This has been a little more involved than I had anticipated. The power windows were working perfectly when I started working on the first project.

First order was to get the climate fan to work w/o blowing the fuse. research lead me to installing an external 30 amp fuse. Opening the fuse box to expose the wiring, I found a melted, hacked mess. Unbolting the wires to #16, I decided to bolt them to an auto resetting 30amp breaker. All said and done, it worked.

While in "the mess", I tried to fix a few other wires.





and the fusebox from above.



W = Window relay.
red circle = #16 fuse Climate fan and #c,d power windows.
Green Arrows = phillips screws to open fuse box.


To be continued...

Generic answers:
Pull the Window Fuses and check the Tips of the Fuse and where the Fuse contacts. (See Pic of what stopped 2 of my Windows from working.) Get rid of any Fuses with a Plastic Body.
Make sure you are getting power to the Fuses.

Pull the Window switches and clean the Contacts (scraped mine with a small pocket knife) inside of the Switches; there is a few DIYs on that.

Pull off the Door Panel and inspect the Window Regulators (on my 123 the Window Regulator Mounting Plates were bent and warped causing the teeth to wear badly); if they are in bad shape your Windows will stop.

Thest the Window Motors themselves by connecting the 2 Window Motor Wires to your Battery to see if you can operate the Windows. Reversing the wires on your Battery reverses the way the Motor Turns. (Unlike your Starter Motor your the Ground is not part of the electrical circuit on the Window Motors.)

If the Switches are good and the Motors are working broken wires where the hinge in doors could be the problem.

I have yet to read of anyone having to replacing the Window Relay so unless you have an other one already to swap and see if that restores power I would look there last.
Attached Thumbnails
Power Windows INOP 1986 W126 300SDL-window-fuse-zz.jpg  
__________________
84 300D, 82 Volvo 244Gl Diesel
Reply With Quote
  #3  
Old 07-22-2010, 02:16 PM
Renntag's Avatar
Registered User
 
Join Date: Jul 2008
Location: Arlington, Va
Posts: 1,289
Diesel 911, Thanks for the tip. My starting this thread was to provide a DIY covering what I learned. As I mention above and many others in this forum, the fuses are often culprit. They may look good, but they could be oxidized. It really is best to buy a large box that includes all amperage's and replace everything, keeping spares in the glove box.

I have also gone through, cleaned and rebuilt many of the switches on my W123, 124, and this 126. Again, helpful advice.

Another point of failure is the plastic slider in the regulator assembly. My left rear window comes loose from the regulator and drops into the door if lowered too far. An inexpensive replacement can be installed if you are crafty enough to figure out how to "peen" over the new pin. I still have to perform this task. I have a DIY coming for that.
__________________
Parting 1987 300TD

87 300TD (crashed for sale)

83 300TD (need rear wiper assembly dead or alive)
98 E300D *sold
86 300SDL Need W126 Blue door panels.
Reply With Quote
  #4  
Old 02-10-2014, 07:27 PM
jia300d's Avatar
Registered User
 
Join Date: Jun 2013
Posts: 28
Hi, I hope you guys get to see my post and help me out.

First, thank you for this info.
Really valuable.

OK, now to my problem.
Yesterday I was changing the RF shock of my 1987 300SDL and while loosening the top nut I accidentally touched the Red wire that feeds the window relay and of course there were some good sparks.

My LF window stopped working.
Soon I noticed that the "c" fuse was blown and I replaced it.
I turned the ignition to check if the window worked but the "c" fuse blew again as soon as power got to it.

Since the RED wire feeds the Window relay I thought that it was probably fried so I replaced it.

Result: the fuse does not blow but when I try to operate the window, each time I press the switch the instrument lights and interior front light dim and I can hear the window motor humming but not moving in any direction.

Any clues out there?
Thanks in advance.


.

Last edited by jia300d; 02-11-2014 at 07:49 AM. Reason: readability
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 Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -4. The time now is 09:54 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, 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