Besides a dealer, where is a good place to buy an ignition switch? I'm after just the electrical part that attaches to the back of the key lock. Mine is so touchy that just turning the key a hair can cause the engine to quit. However, I guess it could be the lock that is worn (290K miles). Is there a way to tell which needs replacing?

Thanks all but $50-$70 seems high for a switch.

your so welcome

You can pull the switch off the back in two minutes with a small slotted screwdriver. A new one is available from the on line retailers such as IPD and FCP. They are not that expensive. If you are good with prying apart pot metal crimps you can clean and maybe adjust your old switch. The cheap, easy to replace electrical portion is the culprit.

mercedesshop.com has them - not too expensive.
things go easier if you use or make a very short slot head screw driver to remove the old switch and the install new one.
position a drop cord light or equivalent so you have lots of light. run the driver's seat all the way back and put something soft on the floor to level it out and make it comfortable while you're lying there doing the switch.

yes, pull plug look at end with mirerr then do by feel