Tbenzo

Greetings to all. I have a 93 400 SEL that's now approaching 175k miles. It's still a really good looking car and never ceases to amaze me on it's performance. It's recently gone through a major tune up and valve cover gaskets. I've replaced the factory wheels with aftermarkets. I went with a 20x9 wheel made by ADR Design, with 245-35-20 in front and 275-30-20 in the rear. It has really changed the look of the car. For the interior, I've add 2 7" headrest monitors with the DVD player custom installed in the rear armrest compartment, so when the armrest is in the upright position, you can't see the DVD player. I'll post pictures as soon as I'm able. Now, let's get down to business. Has anyone ever had the problem of the heat and a/c control working or appears to be working but, there's no airflow. I'm thinking maybe the fan or some type of relay has gone out. Any suggestions?

Peter Guenther

There is always the fan regulator (speed control) that seems to be a common item in the various posts. It sits on the blower motor, about a $250 part. Does the fan speed increase at all if you go to high? Jims page shows how to pull codes from the heater control
http://pages.prodigy.net/jforgione/MB_S500.html

Wintermute

That is my suspicion, too. Having experienced that particular failure, I know that it would exhibit the symptoms that are being described.