Just did it in my 94 E420. I did take pictures in hopes to get it posted. Do a search on all of my previous posts regarding this issue. Purchases a Mallory Sonalarn SC616CPN for the chime.
Anyway, you need to take the cluster out to get to the warning module. Since it's almost impossible to take out the module without pulling out the dash, I just remove one screw to loosen it, unplug it, then take out the guts (buzzer and circuit board).