I got a #46 error code today on my 95 ram 2500 which is high voltage spikes. It only seems to fluctuate out of normal range when the ac is running though. The ac still works and is cold but the voltage moves between 15 and 18 instead of holding a constant 14-15. When the ac is turned off, no problem. Can anyone suggest where to start looking? The alternator is new within 5,000 mi btw.

 

Try checking for an exposed wire going to the compressor shorting to the engine or frame.