Weird Power Fluctuation

[Cmdykstra]

Something strange that has plagued my 1996 993 for quite sometime. When I turn the fan on the CCU to '3' the power to my dash starts to dip? This las time it happened it put my car into 'limp mode'. I was able to reset the ECU and it came back to normal. It's like there is a short somewhere but I'm not even sure how to start looking. My mechanic has never been able to isolate this. Like it's never happened when he has it (something I find a bit hard to believe) Just looking for suggestions. Other than this the thing runs like a dream. Maybe related...the radio will occasional turn on and off....but not all the time? Several years it's done this but never gotten worse.