I did some searching and found some reports of this problem on cars with the "duovalve" system. I have a '95 E300 Diesel w/ 202K. (last year for early body, 6cyl non-turbo) Anyone with some model-year specific info? For awhile, it was just a "lazy" switchover but it's getting worse. At this point, I can't get it to switch over reliably at all. $$ is tight right now so I am trying to avoid a diagnostic at my mechanic if possible. He sugg it that it might be the climate control itself, but after googling around and reading, it seems like it could be a mechanical issue with the valve itself. Are there any PDF schematics posted around the web at all for my series car?

Thanks for any help.

 

Did you solve your problem? I've got a 98 E300 with a similar problem and am also wondering if it is the climate control unit or a mechanical issue with a valve or air door. Passanger side climate control works perfectly - driver's side only blows cold air no matter what the driver's side climate control is set at.

Mark