I made item number 2718962 into a hood ornament. There is a space to put a 5mm LED and run the wire through the ornament. I bought a bunch of 5mm LEDs with 20cm long wires attached from Amazon for cheap.The horn is separate and the LED fits inside it- you can print it with a different color. Designed for my wife who then decided it didn't look right on the car. I redesigned the horn so there shouldn't be a black end to it but didn't reprint it.

please give due credit to the original poster BODY-3D for the unicorn head model.