I'll start by saying I have searched the forums on this till I am bleary eyed. I purchased this roadster in Oct 2011, drove for a bit, and then put it away for the winter in my garage. When I pulled it out in the spring, it had this problem:
1) My blower will only blow at low speed
2) My A/C button is dead, so I can't run the A/C
3) The MAX A/C button is live, but pressing it does nothing
4) The AUTO button is also live, but pressing it only disables the fan
5) Rear Window Defogger button is also dead
6) The Auto Recirc. button is live and appears to work
7) The Max Defrost button is live but does nothing
8) Temp selection and air distribution dials work
So, the non-functioning items are fan speed (beyond low), rear defog, and A/C, therefore I suspect something cooked around the central part of the P/C board. Since three different functions are affected, I can't see it being something downstream of the IHKA control module.
I lived with it for the summer, as I usually had the top down anyway. But, now that it is getting cooler, I really need to have the front and rear defog. available
I expect I will be compelled to replace the IHKA module and get it programmed, unless someone has some other ideas?