It's that climate control again!
 

I can bypass my blower and it works great. I have no power to the plug that goes into the speed control. I have checked the fuse, I have had the control apart on the dash, I have another relay which I installed with no change. Funny thing, I let this car sit for two weeks and the fan control worked! When it quit, it worked for a second then quit, when I hit the defrost button it also worked for a second then quit. Just like a fuse had blown. Does this 560 SL have a long fuse like some of the other styles of Mercedes? I haven't been able to find it so far. Help?

give detqails of your models and series, how do you expect tech person to help you, guessing game? is that not logical?

He said it's a 560SL. :)

I don't know if it has the extra fuse like was added to the W124s.

I'm not sure how you're bypassing it, though. Are you saying you are applying power directly to the motor and thereby bypassing any fuse?

IIRC it's a fuse like the others on the car, i.e. subject to going intermittent if it's old. However, I can tell you from experience that one of the failure modes involves weak contacts in the ignition switch, which will give intermittent HVAC function without interrupting anything else obvious; I figured it out when I tried jiggling the switch (gently!) when it would occur, and finding that I could restart the blower by doing so. The fix is replacement of the switch portion of the ignition assembly, which does not have to mean replacement of the key lock portion.