On My '96 E38 found a reference to this in the Owners Paperwork. It was a Dealer Installed Option from the Reading on the Forum here. Found the brains and turned it on and after troubleshooting I found the Wiring Harness but no receiver. There appears to be an intact round plug that probably plugs into the unit and then 3 wires that have been cut. I'm going to try and crawl under the dash and see if I can lay eyes on the processor. Since it chirps I would think it would be functional and would Just need a Receiver to plug into it