Whats this for, and fans inop
 

I came across a 74 240d that im now restoring. Neither blower works but compressor comes on. I can ground the a/c fan and get it to work manual, so Im assuming a switch or blower resistor is bad, but cant find resistor, and switch look difficult to access.

Also on dash next to buzzer just right of steering column there is a little push-button switch with black rubber cover over it. Lights dim when I push it, but dont see anything working. Any clues?

Thanks,
\Robert

The button almost sounds like a manual glow plug control. My old IH Scout had something like that...but there was a light next to it that lit when the GP's were operating.

Just a thought... :)