2006 CTS base,3.6, non-HID headlights. The right (passenger) side headlights (high and low) are very dim (just noticed yesterday). I have checked both hi and lo fuses and the same relay controls both sides of the vehicle. I suspect I have a faulty ground to the sockets. The wiring diagram in my Haynes manual shows both sockets going to ground. Does any one know if the sockets are grounded with a lug to the chassis and, if so, where is the lug? In other words, how much of the front of my car must be removed to access the wiring? Thanks.