Jeep Articles / Technical and Installation (Headlight If you don?t first upgrade your headlight wiring. Most stock components on a vehicle are designed to a specific level of performance and nothing more. The factory headlights on a Jeep TJ are no exception. They do exactly what they were intended to do: They light up Jeep Headlight upgrade for the YJ Wrangler and XJ Cherokee. Jeep Headlight Upgrade Jeep headlight upgrade is in order for all YJ & XJ's. Yes you can add all kinds of off-road lights on the bumper, below the windshield or even a light bar above the windshield. But in some states it is illegal to run aftermarket lights on the highways.