Greetings.
I just bought a 1987 300SDL and the Becker was not working properly..I purchased a JVC cd player as replacement and got it hooked up and now my factory alarm won't work correctly..I think it has something to do with the large harness with the jumper on the back of the radio and the ground wire that is plugged into the chassis. I have tried several different ways of hooking up the ground wire but seems like there is something in that plug that needs to be hooked up as well..Does anyone know what I need to do? the security system worked perfect before..Thanks a million! John