The idle problem could be either the overload protection relay or once again the idle air valve. If it is OK now, then let it be.

The AC could be a problem with the AC Comp. relay (KLIMA), or any of the inputs that tie into it.

The ballast resistor for the aux. fan is there to step down the fan speed when the red (or green on early cars) switch on the drier turns the fan on. Just check the resistor for continuity. When they go bad they go 'open'. If you jump the red switch on the drier with the key on, then the fan should turn on.