Replacing the ignition tumbler in the 190D is a lot like the 300 model that Dieselgiant portrayed but there are some differences:

The steering wheel has to be removed--you pick out the star in the center and use a big hex socket on the centerbolt underneath. The wheel pulls off without a puller.

To remove the instrument cluster:
In my car I was able to tease the cluster out without the little tools shown in the manual-- it seemed mostly to be just forced into place. Somehow I get the feel it has been removed before!

Drop the column by removing three screws in the turn signal canceling switch, and then carefully sliding the plastic collar off the column, easing the CC switch off, pulling some slack in the CC cable to do so. The collar comes off and lays in the floor wires and all. It does not separate into two pieces. Loosen the column from underneath.

All the wires behind the instrument cluster are self explanatory as long as you remember that its twenty year old wire, and the plugs need to be loosened carefully. I use an electric hair dryer to spray warm air over everything and make things pliable. Start on the left side and unplug each in turn.

The FSM says to detach the speedo from underneath, but I couldnt get my hand through all the wiring to do this. I got the cluster as unfastened as possible, and then found about an inch of slack in the speedocable which was enough for me to get my fingers around the back and loosen it all the way.

Watch the two bulbs on the right-- one is the seatbelt indicator, and one is the glowplug indicator, and you should mark them with tape, the one on the far right being #1 and the other #2.

Dont break the fiberoptic plugs on the upper corners of the cluster, they need to be loosened carefully. I broke one of them.

CLuster out, the rest of Diesel Giants pictorial applies pretty much. You pull and tug and curse, and in the end you have the ignition lock and switch and tumbler on the bench. My lock had the vacuum lines color coded which is important, as noted elsewhere, if you are planning on stopping the car later...

The electric switch on the ignition lock controls the warning buzzer. remove it by sliding a tiny screwdriver underneath it and sliding it out of its track at the same time.

I spent a lot of time getting the tumbler free until I noticed that the FSM shows the removal tools have a chisel point on them, which helps to find the release. Get everything right and it falls apart easily.

I replaced both lock cylinder and ignition switch since both were worn to dust. And lets face it--you dont want to do this twice.

Reverse for installing, but take your time and dont resort to brute force--theres a lot of plastic in there. This is doable but requires a light touch and a lot of time.

Better than sitting alongside the road with a frozen lock.