I've tested this morning and got zero reading at both fuses "a" and "b"
Wiggling the key in the ignition did not do anything.

OK, so we're on the right track.

There must be a relay that provides power to these fuses when the ignition switch closes.

Just need someone with an electrical schematic of this vehicle to confirm where it is.

I have the W126 schematic.
 

F7 provides power to the window relay (located in the fuse box).
The contacts of the window relay are powered by a red wire off of the terminal strip on the RH fenderwell.
From there, the contacts provide power to fuses (Fh and Fg) that power the "diagonal" FR and LR, FL and RR sets of motors.
The switches work to alternate power/ground for each side of the motor for direction.

The ground side of the relay is shared with the interval wiper control, rear defogger, and window switches and motors.

Your problem seems to be pointing to the window relay.

Cool wind in my hair
 

Thank you all. It was F7. It did not show any damage, but when I removed it, at closer inspection there was a deep circular groove at both tips form sustained pressure, I suppose.

Good job.

Now, will you kindly take our collective advice and replace all fuses in the box with proper copper or brass fuses?

I can't tell you how many times we chase a problem like this, only to find out that the fuse is NG (but it looooooked goooooood............... :eek: )

Got a full set of fuses. All brass. Will replace the whole box tomorrow at daylight. Thank you again.

Michael.

may have done this
 

already but you might want to clean the little copper tabs the fuses sit in too. a small pocket knife twisted works well.

tom w

Excellent.

And follow the advice from Tom, above.

Help is what we do here.

This would not be the first time I have been told to replace 'good looking' fuses. In an effort to save money buying fuses locally at an arm and a leg, can anyone recommend an online source to get a large assortment of W123/124/126 friendly fuses at a reasonable price?

Great thread !

Thanks.

click the buy parts link above.
fuse kits in the electrical list.
fastlane or allpartsexpress
APE, http://www.allpartsexpress.com/ShopByVehicle.epc?q=1983-MERCEDES--BENZ-300tdt--/--L5_3.0l_diesel_turbo-Electrical&yearid=1983&makeid=MERCEDES+BENZ%40%40MERCEDES+BENZ%40%40X&engineid=1194320%40%40300TDT++ %2F+L5_3.0L_DIESEL_Turbo%40%40300TDT&catid=Electrical&subcatid=Fuse&mode=PA
or fastlane smaller packs...
http://catalog.peachparts.com/ShopByVehicle.epc?q=1983-Mercedes--Benz-300td-Body--Electrical&yearid=1983%40%401983&makeid=63%40%40MERCEDES+BENZ%40%40X&modelid=6232%3AMBC|1518%3AED|10 000135%40%40300TD&catid=241959%40%40Body+Electrical&subcatid=241971@@Fuse&mode=PA
again fastlane assorted kit
http://catalog.peachparts.com/ShopByVehicle.epc?q=1983-Mercedes--Benz-300td-Body--Electrical&yearid=1983%40%401983&makeid=63%40%40MERCEDES+BENZ%40%40X&modelid=6232%3AMBC|1518%3AED|10 000135%40%40300TD&catid=241959%40%40Body+Electrical&subcatid=242443@@Fuse+Kit&mode=PA

Thanks for the link. I think the next order I place, I will add the 100 packs to get closer to free shipping.


Does anyone have a link to, or info to share showing the wiring for the power window system on a 1986 300SDL ?

I am trying to find what wires in the fuse box feed the window switches in the console. I opened up the fuse box to repair a melted heater-a/c fan fuse and found a mess.

Windows were working prior to my repair. I can only assume something has come loose. Knowing what colour wires to look for may speed up the process this weekend.

Thanks in advance.

The power window relay in the fuse box feeds fuses "c" and "d". "c" runs LF and RR. "d" runs RF and LR.

Check for voltage at "c" and "d" as a first step.

Brian,

Thanks for the info/help. I guess I didnt make my post clear enough. I literally found a mess. There are several fuses that are not in place at all, the wiring that should be bolted to the power window fuses you mention, are not attached. There are several aftermarket fuses installed and tucked in under the "front side" of the fuse box.

My power windows worked perfectly until I performed a climate/ a/c fan fuse upgrade. After that work ws completed, my fan worked (for more than a couple minutes), but then the windows no longer operated.

I have small windows of time to work on the car and would like to maximize my time. I have searched for a wiring diagram for this car and I come up with nothing.

I would LOVE to have a large diagram that I can print out and reference while working on the car.

Thanks in advance to anyone that can help.

Update:
here is my fuse box wiring.

http://www.peachparts.com/shopforum/...pictureid=2406

Gentlemen,

I was stung by the power window gremlin yesterday. Perhaps I have a "good" fuse that is really bad but I doubt it. Apparently, the circuit on the 1985 300SD links the left front and the right rear and vice versa. The passenger side front window does not work all of a sudden. No groaning or chattering warnings. Stopped. The driver's side rear works! The circuit has to be hot.

Sounds like a console switch or a motor, eh? Somebody tell me something easy so I can put my baby back on the road.

Thank You,
Joe Marroso

The wiring for the vehicle is provided in a book that's about 50 pages long and includes all the systems other than the climate control. There is no easy way to send such a "diagram".

The person who previously worked on that fuse box should be shot.