Neil,

As I suspected, the problem was a short in the turn signal/wiper switch. The good news was that this was all it took. The bad news was the not-insignificant cost of the parts and labor (more than $200 total, as I recall).

Hope this helps.

__________________
David

2010 E350 Coupe / 1K miles
2007 ML350 / 18k miles (Gone, gone, gone!)
1995 E320 Wagon / 170k miles
2008 Audi A6 4.2 / 12k miles
2006 Mitsubishi Endeavor / 25k miles