I will say right now that these 2 problems happening might be a coincidence. I have two electrical problems on my 2006 GS: 1 my stereo won't work and throws a "E com" error on the screen. 2. the ac compressor won't engage. I checked the wire going to the compressor with the a/c on and there is no signal, so I assume it is electrical somewhere up the line. Is it possible these two things are related? such as a common connector some where that may have suffered a corrosion problem? I'm no stranger to doing electrical work on; vehicles, farm equipment and metal working machinery. I guess, since this car is getting old and I would really like rebuild/restore it I should get a complete manual.