Thanks for reply. All the dash lights come on, but starter does not crank on final 1/4 turn of key. Cold or hot doesn't matter. The car is apart right now and few weeks will have chance to get it back together. Get yourself a remote starter. Two alligator clips to back of starter and I bet car cranks up immediately. This way you will not get stuck. I am going to try to fix problem . I know I could permanently hard wire with a pushbutton switch to dash to start, but I will try to fix it the correct way. I have replaced ignition switches before and $1000 sounds high. Check all your fuses and relays.
The dealers are always insanely expensive. I would not own 3 Mercedes if I had to go to the dealer for all repairs. I have been working on Benzes for over 30 years. Try to find a local MB mechanic and get a diagnostic check from them. Also there are OBD codes that may indicate problem. The engine harness cable on these cars are biodegradable, check to see that yours is ok. I replaced mine myself, cost me about $300 for cable and took me about 45 minutes for installation. Very easy job. If you need instruction just let me know. Will get back with you about any progress as soon as I get time to finish putting things back in my w140 1993 300SD diesel. I like working on these cars when I have the time.