W210 electronic ignition switch 'clicking' sounds

[scott19_68]

The electonic ignition switch (EIS) in my 1998 E300 had started to make a random clicking noises a few months ago that sounds like a relay opening and closing. By lightly jiggling the key while in position 2, it clicks rapidly. It did not seem to have any impact in starting the car so I have been ignoring it up until now. I'll come back to this in a second...

When I brought my car in for an inspection last week the mechanic failed it because the horn would not work! After cleaning the spade terminals and checking the relay, still nothing. The next morning after starting the car I tried the horn and... success! Then, after driving to work and parking the car I tried it again and... nothing.

After a few days of trying to correlate the horn function to something (time, vehicle temperature, etc.) I finally stumbled onto what is going on. If I slightly push the key in the ignition in the 12-o'clock direction and hold it, horn works great. Conversely, if pushed in the 6-o'clock direction, no horn. I'm assuming the PO had a heavy keychain hanging off the key.

So, I betting a new EIS would fix it but I want to check with the experts on this board first on a possible DIY. Can the innards of the EIS be extracted and cleaned? I've had quite a few cases of electrical components on working properly on this car and every one of them was easily fixed by cleaning some contacts (side marker lights, fog lights, radio volume knob, and combination switch).

Any advice is appreciated.