Doug,
Have you checked the blower fuse? To properly check it you should remove it from the holder. They'll get hairline cracks that are invisible to the eye but will fall apert when their unscrewed from the holder.
Hazen Arnold
91 300TE 4Matic
134k mi.
P.S. You can call or e-mail this guy. He is the guru of ACC and cruise control. He is a competitor of Mercedes shop, si I'm a bit leary of posting him here.
george_murphy@compuserve.com
865-482-9175
9 am to 5 pm ET voice or fax