More knowledge is just more insurance of a great repair.

Switch cleaning worked for me
 

Just wanted to give a shoutout to this thread as it helped me diagnose and fix my dead turn signals. Hazards worked, signals didn't. So I pulled the console, disconnected the hazard, and tried the wire shorting trick. Signals worked. So I took the switch inside, gently took it apart and cleaned, and all is well.
I love car people.

Might be a little off topic - maybe I should start a new thread - but I've been wondering whether it would be feasible to replace the older style console and its switches with a newer console (like in 83 -85 w123 or W126) - I have some of both styles (and some consoles with no switches); the older style switches (with the chromed plastic bezels) in my '80 model 300cd are not as robust nor as easy to maintain as the newer thinner switches (without the chrome) on the later model W123. I have picked up some of the female connectors for the newer style switches but haven't yet dug into the wiring differences - and I seeem to recall that there are some differences. Has anyone tried this upgrade?

Bob, Great job. Thank you for sharing it with us. If you don't mind I would like to add 2 things that I learned over the years.
First, for cleaning electrical contacts I use a a pencil eraser followed by WD40 to clean out any rubber crumbs that may have come off. The eraser polishes the contacts but doesn't remove any of the contact itself. If the contacts are really pitted then use whatever is needed to clean them then polish with the eraser.
The other thing you didn't mention is that the center of the contact plates where they pivot is also an electrical contact. So each switch has 6 contact points, 3 or each side.
The first switch i cleaned still failed to work because of this center contact. It is not as obvious as the other 2 contacts.

Thanks again.

PaulM

Good points Paul

1982 300d -

If both of my rear door window switches aren't working - but both rear windows work fine when operated from the center console switches - can I assume(hope) that the little square button in the middle of the console switches needs a cleaning?

Is there a good pic showing how I should lift up the center wood panel to get at the switches? Do I need to remove the gear shifter or anything?

I don't know about the 300D but the SD console wood trim slides forward to unlock then lifts for removal. The SD has a plastic tray just in front of the wood trim which has to be lifted from it's front to be removed. It locks the wood trim in place by preventing it from sliding forward.

It seems I remember the ash tray has to come out to access the front of the plastic tray.