Certain vehicles were produced without the required dielectric grease being applied to the rear light bulb socket assemblies. Absence of the grease can result in electrical arcing between the light bulb major filament contact and the socket terminal that can render the stop and turn signal bulb inoperative. An inoperative rear turn signal lamp will not convey the driver's intention to turn to drivers in following vehicles. If a stop lamp is inoperative, indication of brake application to a following vehicle will be reduced, although during braking, warning to the rear of the vehicle will be conveyed by the remaining functional stop lamp and the center high-mounted stop lamp. Correction: Dealers will replace the rear lamp bulb socket assemblies.