20 Most Recent Sony CDX-M800 CD Player - Page 7 Questions & Answers

it goes to dash lights it allows the radio to dim out when you turn lights on

Sony eSupport XM 2165GTX Support Sony eSupport XM 2165GTX Contact Support Chat and phone support at link above.

It doesn’t have to be a Sony controller any one would work as long as the plugs are the same size.

Did you check the terminals on the speakers? Sometimes the colors of factory wiring in the cars, differ from the standard used in commercial car-audio... Try checking continuity with a multimeter.