Several months ago, the climate control in my 2000 Maxima began acting
up.  It would be working fine and then suddenly all the lights would
come on and I would have no control.  It basically had a mind of it's
own, but generally acted as if it were stuck on 65 degrees.
Occasionally there would be no lights at all but the fans would still
run randomly.  When the problems first started, I would have no control
for the first 2 or 3 minutes after starting the car but then it would
start working fine.

After about a week or so of it cutting off and on, I was never able to
regain control.  Thinking it was just a bad controller, I brought it to
the dealer, and they said that it was indeed a bad controller and that
they would order the part (about $550).  Since it was not a critical
problem and I was busy with work, I decided instead to wait a few weeks
and then buy a used controller on ebay (for about $35).  However, when
I hooked it up, nothing lit up, just like before, and I had no control.

Interestingly, when I hit the rear defroster button on either of the
two controllers, I hear a click and the lights dim, suggesting that it
is indeed working.  However, no other controls respond at all.

I really don't get a good vibe from the dealer and I was wondering if
anyone had an idea what the problem could be.  Seemed pretty obvious
that it was the controller, but apparently it wasn't.

Thanks a lot.