This is on a 76 450sl, with the 4 levers and two ***** HVAC controls. The blower motor randomly goes on and off full blast. If the switch is on one of the 4 speeds, the blower will alternate between full blast and whatever the selected speed is. Doesn't matter if the car is sitting still or moving. Today I finally decided to pull the control panel off and disconnected the switch thinking it might be it. Even with the switch removed, ignition on but engine off....just sitting there in my garage...it would come on and off at it's own demon possessed will. It does not come on with the ignition off. Any suggestions on what to look at next? I feel like there is some short somewhere but just not certain what my next step should be...but I'm tired of driving down the road in silence then all of a sudden the blower kicks on and I have a mini stroke. Thanks for your help!

 

Still no resolution. Today put in brand new regulator and still does it. assuming that means a short somewhere

 

maybe climate control amplifier or blower relay, unlikely.