I have a 1995 S320 with a defective climate control system. I replaced the blower regulator on top of the blower motor several months ago, and all was fine for a while, but now I have a different problem.

When I am driving, the blower will come on full blast or, more commonly, will shut down and illuminate the "0" button. I can restart it immediately by pressing the "Auto" button and then it will behave for a while. Just before it goes dead, it makes a distinct clicking noise on the right side of the passenger compartment. Hard to pin point it while driving, but it sounds like it is just to the right and above the glove box.

Is there a potentially defective relay there? That is the only thing I can think of that would make such a sound.