Description: Genuine GM Headlamp Dimmer Switch, part number 26019660. This GM OEM headlamp dimmer switch provides the vehicle's forward low- and high-beam lighting, with factory-correct beam pattern, mounting points and connectors. Made by General Motors to original equipment standards for correct fit, finish and durability—no guesswork with aftermarket parts. Verify fitment using your VIN or GM part number 26019660 before ordering. Shipped from Gateway Buick GMC, an authorized GM dealer.