Contour Enthusiasts Group Archives Forums Modifications Audio Is it pos. to add an input jack to a car stereo?

I know some people with different cars that have traced the connections and soldered onto something to get an AUX IN on their factory stereo but it seems like a real mess most times. how about somehting like

Alpine CDM-9801

OR you could look around any see if you can find something like DEH-4100 (what I have) and the the p-bus adapter for AUX IN.