while I was bolting in my heater core, I had to remove some kind of radio looking box bolted with brackets onto the firewall---under the passenger side -I dont have a scanner, but I will describe it----It's metal-about 10- inches by 4 inches-writing on it says-------6/12 umschaltanweisung an Deckel Innenseite-----then below that it says-6/12 change-over instructions in cover inside 150 E 9000- 04-Ithere are wires that I cut years ago-I think it was something to do with the original radio-help if anyone knows