The brake light switch in your Cherokee controls the illumination of the brake lights at the rear of the vehicle. An improperly functioning switch might not illuminate the brake lights. This type of failure makes road travel unsafe because other drivers will not know when you are bringing your Cherokee to a stop. Other than car horns blaring, one of the first signs of a defective brake light switch involves trouble with moving the gear shift on automatic transmissions. Locate the problematic switch, and replace it, if needed, right at home. Finding it will take just five minutes to do; the repair will take you an additional 35 minutes to complete.
Open the driver's door on your Cherokee. If the driver's seat moves electrically rather than by a seat release lever, push the button required, and move the seat back as far as it will go. Kneel or bend down, and position yourself so you can see underneath your Cherokee's dashboard.2
Follow your Cherokee's brake pedal shaft-bar from the floor, up 12 inches to where it connects under the dashboard. The shaft-bar is the metal bar the rubber brake pedal pad attaches to in the front.3
Identify your Cherokee's brake light switch beneath the dashboard. The small component one inch below the brake pedal shaft-bar's connection is the brake light switch. The switch looks similar to an ink pen and has two wiring harnesses connected to the rear side of it. The front of the brake light switch has a small plunger on it that resembles a round doorbell buzzer.