1997-2002 Ford Expedition High Mount Stop Lamp: Fixing Leaks & Lights

Symptoms of Failure

Diagnosing a faulty high mount stop lamp on a 1997-2002 Expedition is usually straightforward. The issues typically fall into three categories: the light itself, the seal, or related electrical components.

1. Light Does Not Work

This is the most common symptom. When you press the brake pedal, the main brake lights will work, but the high mounted lamp remains off. The cause is almost always a burnt-out bulb. Since the housing contains three bulbs, it's possible for one or two to burn out before you notice a complete failure. Less commonly, corroded bulb sockets from water intrusion or a damaged wiring connector can also cause the light to fail.

2. Water Inside the Lamp Housing or Leaking Into the Cabin

If you notice condensation inside the red lens or find water stains on your interior headliner near the rear liftgate, the lamp's foam gasket has failed. This is an extremely common issue on these vehicles. The original foam gasket becomes brittle and compressed over time, losing its ability to seal against the vehicle body. This allows rainwater to seep past the seal, either collecting in the lens or running down into the headliner and cabin.

3. Flickering or Dim Light

A flickering or dim light often points to a failing bulb that is about to burn out completely. It can also indicate a poor connection at the bulb socket, often due to minor corrosion, or a problem with the vehicle's main brake light switch. If all your brake lights (not just the high-mounted one) are acting erratically, the brake light switch located at the top of the brake pedal arm may be the culprit.

Known Issues, Recalls, and Technical Service Bulletins (TSBs)

While the lamp itself is simple, it's connected to systems that have been subject to recalls and service bulletins.

Recall 05S28 / NHTSA 05V-388: Speed Control Deactivation Switch Fire Risk

This is a significant safety recall affecting 1997-2002 Expeditions. The brake pressure switch for the cruise control system, located on the brake master cylinder under the hood, could leak brake fluid. This fluid could corrode the switch's electrical components, leading to a risk of overheating and fire, even when the vehicle is parked and turned off. A faulty switch could also cause the brake lights to stay on or not work at all. Ford's remedy was to install a fused wiring harness to prevent this issue. Verify if this recall has been performed on your vehicle.

TSB BC9673961001: High Mount Stop Light Stays On

An early Technical Service Bulletin was issued for conditions where the high mount stop light would remain illuminated. This is typically caused by a misadjusted or faulty brake light switch, which fails to open the circuit when the brake pedal is released.

Buying a Used High Mtd Stop Lamp

A used OEM lamp is often a better choice than a cheap aftermarket alternative, as many aftermarket units use poor-quality gaskets that can leak from day one. When inspecting a used OEM lamp, here’s what to check:

• Check for Cracks: Carefully inspect the red lens and the black plastic housing for any cracks or signs of damage. Pay close attention to the screw mounting holes, as overtightening can cause them to crack.
• Examine the Lens Clarity: Look for heavy fading, haziness, or yellowing from UV sun exposure. A clear, vibrant red lens is safer and looks better.
• Ignore the Old Gasket: Assume the foam gasket on any used part is bad. It will be compressed and brittle. Plan to replace it. You can buy a new, thicker aftermarket gasket or create your own from weatherstripping.
• Inspect the Bulb Sockets: Twist out the bulb sockets and look inside. Check for any green or white crusty corrosion, or signs of rust from water damage. Clean contacts are essential for reliable operation.
• Verify Part Numbers: Ensure the part is a genuine Ford component. Look for OEM numbers like F75Z-13A613-AE.

Cost Comparison

The cost to fix a faulty high mount stop lamp can vary significantly depending on the solution you choose.

Replacement Guide (DIY)

Replacing the high mount stop lamp on a 1997-2002 Expedition is one of the easiest repairs you can do. No interior panel removal is required.

• Difficulty: 1/5 (Beginner)
• Time: 15-20 minutes
• Tools Needed: Phillips head screwdriver (Some models may use a T20 Torx driver)

Step-by-Step Instructions:

1. Open the rear liftgate to get a comfortable working angle.
2. Locate the screws on the exterior face of the lamp assembly. There are typically four Phillips head screws.
3. Carefully remove the screws and set them aside.
4. Gently pull the lamp assembly away from the liftgate. It may be slightly stuck due to the old gasket.
5. With the lamp free, twist each of the three bulb sockets about a quarter-turn counter-clockwise and pull them out of the housing.
6. To replace bulbs, simply pull the old bulb straight out of the socket and push the new one in. The correct bulb type is 912.
7. Thoroughly clean the mounting surface on the liftgate, removing all residue from the old gasket.
8. Place a new gasket on your replacement lamp assembly.
9. Insert the three bulb sockets into the new lamp and twist clockwise to lock them in place.
10. Position the lamp on the liftgate and reinstall the mounting screws. Tighten them evenly until snug, but do not overtighten, as this can crack the plastic housing.
11. Have a helper press the brake pedal to confirm all three bulbs light up correctly.

Frequently Asked Questions (FAQ)