1997 Chevrolet Malibu High Mount Stop Lamp: Fitment Traps and Water Leak Fixes
This guide covers diagnosing, replacing, and finding the correct high mount stop lamp for the redesigned 1997 Malibu, avoiding common compatibility and water leak issues.
- This part ONLY fits the redesigned 1997 Chevrolet Malibu and 1997 Oldsmobile Cutlass sedans; it does NOT fit the 1997 Cutlass Supreme.
- Water leaks into the trunk are a common problem caused by a failed gasket on this lamp, which can lead to corroded sockets and repeat bulb failures.
- Before buying a used lamp, inspect the mounting tabs, lens, and electrical connector for damage or corrosion.
- Replacement is very easy for a DIYer, requiring minimal tools and less than 20 minutes to complete.
Critical 1997 Model Year Compatibility Information
Warning: The 1997 model year is a major point of confusion. This high mount stop lamp fits the all-new 1997 Chevrolet Malibu sedan and its nearly identical twin, the 1997 Oldsmobile Cutlass sedan. It does NOT fit the 1997 Oldsmobile Cutlass Supreme, which was an older, different model also sold that year. Before purchasing, visually compare your old lamp's shape, mounting points, and electrical connector to the photos of the replacement part to guarantee a match.
Symptoms of a Failing High Mount Stop Lamp
Failure of the third brake light can range from a simple annoyance to a serious safety hazard. Here are the most common symptoms:
- Light is Completely Off: This is the most obvious symptom. When you press the brake pedal, the light does not illuminate at all. The cause is typically a burnt-out bulb, a blown fuse, or a wiring issue.
- Flickering or Intermittent Operation: The light may flicker or work only some of the time. This often points to a loose bulb, a corroded bulb socket, or a poor connection at the electrical plug.
- Dim Light Output: If the light seems dimmer than it used to be, it could be due to an aging bulb, corrosion on the electrical contacts causing high resistance, or a failing gasket that has allowed the lens to become dirty or hazy on the inside.
- Water Leaks in the Trunk: A common failure point for these lamps is the foam or rubber gasket that seals the housing against the car's body. When this gasket dries out and cracks, it can allow water to leak into the trunk area, often pooling in the spare tire well.
Known Issues for This Generation
Water Leaks from Gasket Failure
While no specific recalls or Technical Service Bulletins (TSBs) exist for the 1997 Malibu's high mount stop lamp, a common problem on this platform and other GM vehicles is the failure of the lamp's sealing gasket. Over time, the foam gasket compresses and degrades, breaking the seal between the lamp and the car body. This allows rainwater to seep into the trunk.
This water intrusion can cause several related problems:
- Corrosion in the bulb socket, leading to repeated bulb failure.
- Rust in the trunk floor or spare tire well.
- Mold and mildew growth in the trunk carpeting.
When replacing the lamp, it is critical to use a new gasket or a lamp that comes with a fresh one. Ensure the mounting surface on the car is clean and dry before installation.
Buying a Used High Mount Stop Lamp
For a part like this, a quality used OEM lamp is often a better choice than a cheap aftermarket copy. Original GM parts have superior plastics that resist fading and cracking, and they guarantee a perfect fit. Here’s what to check before buying a used one:
- Inspect the Lens: Look for any cracks, deep scratches, or significant fading. Minor hazing can sometimes be polished out, but a cracked lens will leak water.
- Check the Housing and Mounting Tabs: The plastic housing should be free of cracks. Most importantly, verify that all mounting studs and plastic alignment tabs are intact. Broken tabs will prevent the lamp from seating securely, leading to water leaks.
- Examine the Gasket: Check the condition of the foam gasket. If it's flat, brittle, or crumbling, it must be replaced. If the used lamp doesn't come with a good gasket, you may need to source one separately.
- Look at the Electrical Connector: The connector pins on the lamp housing should be clean and free of any green or white corrosion. Corrosion is a major red flag indicating past water damage.
Replacement Guide (DIY)
Replacing the high mount stop lamp on a 1997 Malibu is a simple task that most DIYers can complete in under 20 minutes.
- Difficulty: 1 out of 5
- Tools Needed: No tools may be required if it uses wing nuts, but a 10mm socket or wrench might be needed for hex nuts.
Step-by-Step Instructions:
- Access the Lamp: Open the trunk. Pull back the trunk liner or headliner at the top of the trunk opening, directly behind the lamp. You should see the back of the lamp and its mounting studs.
- Disconnect Wiring: Squeeze the tab on the electrical connector and pull it straight off the lamp housing.
- Remove Nuts: Unscrew the two or three wing nuts (or 10mm hex nuts) that hold the lamp in place. Keep them in a safe place.
- Remove the Old Lamp: From the outside of the car, carefully pull the old lamp assembly away from the body. It may be slightly stuck due to the old gasket.
- Clean the Surface: Thoroughly clean the area on the car where the lamp mounts. Remove any old gasket residue, dirt, or wax to ensure the new gasket can create a perfect seal.
- Install the New Lamp: Position the new lamp, making sure its mounting studs and any alignment pins go through the correct holes.
- Secure the Lamp: From inside the trunk, hand-tighten the nuts. Tighten them evenly in a crisscross pattern to ensure the gasket compresses uniformly. Do not overtighten, as this can crack the plastic housing. A torque of around 4.7 Nm (42 lb-in) is a good target if you have a small torque wrench.
- Reconnect and Test: Plug the electrical connector back in. Have a helper press the brake pedal to confirm the new light works before putting the trunk liner back in place.
Cost Comparison
| Part Type | Estimated Price Range |
|---|---|
| New OEM (GM) | $100 - $150 (Likely discontinued, availability is scarce) |
| New Aftermarket | $50 - $90 |
| Used OEM | $30 - $60 |
| Shop Labor Cost | $40 - $80 |
Technical Specifications & Part Numbers
| Specification | Value |
|---|---|
| Vehicle Fitment | 1997 Chevrolet Malibu, 1997 Oldsmobile Cutlass (Sedan only) |
| Verified OEM Part Numbers | 5978371, 05978371 |
| Common Aftermarket Part Numbers | Dorman 923-245 |
Frequently Asked Questions (FAQ)
My third brake light is out. Do I have to replace the whole assembly?
Not usually. The most common cause is a burnt-out bulb. You can typically access the bulb socket from the trunk, twist it out of the lamp housing, and replace just the bulb. However, if the housing is cracked, the lens is faded, or the socket itself is corroded from a water leak, replacing the entire assembly is the best long-term solution.
Will this part fit my 1997 Oldsmobile Cutlass Supreme?
No, it will not. The 1997 Cutlass Supreme is a different body style. This lamp only fits the all-new 1997 Chevrolet Malibu and the new-for-1997 Oldsmobile Cutlass sedan, which share the same platform.
I replaced the bulb and checked the fuse, but the light still doesn't work. What's next?
The next most likely culprits are the brake light switch located on the brake pedal arm, or a problem in the wiring. Check for corrosion in the bulb socket and the main electrical connector first. If those look clean, you may need to use a multimeter to test for power at the socket when the brake pedal is pressed to determine if the issue is the switch or a break in the wire.
How can I prevent the new lamp from leaking water?
The key is the gasket. Ensure your replacement lamp (whether new or used) has a fresh, pliable gasket. Before installation, make sure the mounting surface on the car is perfectly clean and dry. When tightening the nuts, apply even pressure so the gasket seals uniformly. Do not overtighten.
Technical Specifications
OEM Part Numbers: 05978371 5978371
Fits 1997 Chevrolet Malibu and 1997 Oldsmobile Cutlass (non-Supreme models). Typically secured with 2 or 3 nuts from inside the trunk.
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Chevrolet Malibu:
- Critical 1997 Model Year Compatibility Information
- Symptoms of a Failing High Mount Stop Lamp
- Known Issues for This Generation
- Water Leaks from Gasket Failure
- Buying a Used High Mount Stop Lamp
- Replacement Guide (DIY)
- Cost Comparison
- Technical Specifications & Part Numbers
- Frequently Asked Questions (FAQ)
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