I'm looking at a 1982 300SD for purchase, but the windows do not operate. Also the mirror adjuster switch that sits between the windows switches does not move the mirror. The fuses all look good. Does anyone have any ideas what possible things might be wrong. Just looking for an idea of what I might be getting into?

Thanks.

 

Below is a pic of one of my Window Fuses. As Forcedinduction said it looked good a first. But, when I pulled it out I got a surprise.
One Fuse connects to 2 windows 1 front and 1 rear; however they are acrossed from each other.
Anoter common problem area can be the Switches. They get full of crud and the Contacts inside the switch get burned up a little.
In the last pic below you can see the the red arrow pointing to one of the burned contacts, but, they are all burned to some degree. I scraped them carevully off with a knive and the Window worked again.

 

I forgot to add there is also a Power Window Relay behind the Instrument Cluster. However, I have not read of anyone having to replace one yet. But, I also have not read of a case where none of the Windows function at all.

Normally some will work or at least partly work.

If both Rear Windows will not work there is a Child Safety Switch that can go bad and it will cut off the power to the rear windows.

 

You can test the window motor with a 9V battery. Behind the door skin is two wires that come from the motor.

They screwed to two other wires going to the relay.

Unsrew the wires and put the 9V on the window motor wires only. Should do something. + on + and - on - is " up " and + on - and - on + is " down "

If you want a little more power you can use a set of jumper cables off you battery. But a regular 9Volt battery is a little easyer.

Also its a good idea to clean out the gunk from inside the window switches like the above post said to do. I have had a switch stick down and blow my window motor.

Hope it helps.
Jay

 

None of the windows work on our 1991 560. Likewise, the seat functions won't work either. Two weeks ago, just stopped working! Fuses ck ok.

Help!

Thanks.

 

German fuse box. Take all of the fuses out and clean each and everyone of the contact points. Alot of mechanics will change the whole fuse box. It's easyer and they make more money.

 

I have not read enough threads or posts concerning the newer models past 1985 to know if they have the same problem areas.

My general approch is check the Fuses, The Switches, Remove the Door Panel and see if the Window Motors and Wnidow Regulators work.
If you cannot get the Motors to work using Jumper Wires running from in my case an extra Battery and the Window Regulators seem OK I would suspect the Brushes in the Window Motor to be worn or some other issue inside of the Motor.

If the Switches are OK when you take them apart and the Windows work when you use Jumper Wires but not when you use the Switches I would suspect damaged wires where they flex when the doors open and close.