I have a 92 500SEL and in the instruction manual it mentions a Diagnosis Mode for the Automatic Climate Control. What does this do? How do you get into it. The reason I ask is today the temperature outside was in the 80's. My wife had been driving my car and when I got in and turned on the A/C the air conditioner did not work. The red light came on on the Auto button and also on the EC button and refresh button but the unit would not push out any air. I turned the car off and tried again but that did not reset it. I waited to later on tonight and the outside temperature went down to 70. I turned the dial button to Auto and pressed the Auto button, this time the blower came on and the unit proceeded to cool the interior. Can anyone think of why the unit would not work in higher outside temperature? I also see in the manual that when the temperature is high outside that "the system engages the recirculated air mode". Could there be someting not engaging correctly based on the high ambient temperature?

Thank You
Fred Berry

Have you go check pro's tech tip at 5-5-99
I have post about 140 air condition blower
inopative.
hope is help.