I have a 2006 300c without factory HID's. I've done some searching, but to no avail. Anyway, I tried installing an aftermarket HID kit and the lights only work when the car is off. I'm not using relay(s) or any kind of resistor either. The brand is Kensun, and I've had good luck with them in my Mustang and Dakota. Any thoughts? Thanks.

 

your ballasts are putting out too low of a voltage for the FCM (front control module). FCM thinks it's a short so kills that circuit to prevent any further electrical damage back to the vehicle.

you need to use the appropriate relay kit for your light kit to power your ballasts directly from the battery.

nature of the beast with the 300 vehicles.