1990 Buick Regal Rear Side Marker Lamp: A Buyer's and Troubleshooter's Guide
This guide covers the common failure points, inspection tips for buying a used unit, and replacement basics for the 1990 Buick Regal's rear side marker lamp.
- The most common failure is a simple burned-out bulb, but corrosion in the socket is a close second.
- When buying a used lamp, the most critical inspection is for intact mounting tabs; broken tabs mean the part won't fit securely.
- New OEM and complete aftermarket assemblies are very difficult to find; a good-condition used OEM part is the most realistic option.
- This is a very easy DIY repair, typically requiring only basic hand tools and access through the trunk liner.
Symptoms of a Failing Rear Side Marker
Failure of the rear side marker lamp on a 1990 Buick Regal is typically easy to spot. The signs usually point to one of a few common causes related to age and exposure to the elements.
- Inoperative Light: The most obvious symptom is the light not turning on at all. This is most often caused by a simple burned-out bulb, which is the first thing to check.
- Dim or Flickering Light: A light that is noticeably dimmer than the other side or flickers intermittently often points to a poor electrical connection. This could be caused by corrosion inside the bulb socket or a loose wiring connector.
- Moisture or Condensation Inside: Seeing water droplets or a foggy appearance inside the lens is a clear sign that the housing's seal has failed. This moisture will quickly lead to corrosion on the bulb and socket, causing electrical failures.
- Cracked or Hazy Lens: Over decades of exposure to sunlight and weather, the plastic lens can become brittle, cracked, or cloudy. A cracked lens allows water to enter, while a hazy or yellowed lens significantly reduces the light's brightness, making the vehicle less visible.
Known Issues, TSBs, and Recalls
For the 1990 Buick Regal, there are no known Technical Service Bulletins (TSBs) or safety recalls issued by the National Highway Traffic Safety Administration (NHTSA) that specifically address the rear side marker lamps. While the vehicle has been subject to recalls for other components like seat belts and suspension parts, the exterior lighting has not been identified as having a widespread manufacturing defect.
The primary "issue" for this part is simply its age. Plastic materials become brittle over 30+ years, seals dry out, and electrical sockets are prone to corrosion from moisture. Failures are almost always due to normal wear and tear rather than a specific design flaw.
Pro Tip: When a bulb burns out, take a close look at the socket. If you see any white or greenish crust (corrosion), clean it out with a small wire brush or electrical contact cleaner before inserting a new bulb. This prevents the new bulb from failing prematurely.
Buying a Used 1990 Regal Side Marker: What to Check
Since new OEM and aftermarket assemblies for this specific model are scarce, a quality used OEM part is often the best and only option. Before buying, perform a careful physical inspection to avoid common problems.
Inspection Checklist:
- Check All Mounting Tabs: This is the most critical inspection point. The lamp assembly is held in place by plastic tabs and studs. Carefully inspect each one to ensure it is present and free of cracks. A lamp with a broken tab will not mount securely to the vehicle body.
- Examine the Lens for Cracks: Hold the lamp up to a light and look for any hairline cracks, especially around the edges and mounting points. Even a small crack will let in water, leading to bulb and socket failure.
- Assess Lens Clarity: Look for hazing, yellowing, or fading from UV damage. A clear, vibrant red lens is safer and looks better. While minor hazing can sometimes be polished, a deeply faded lens should be avoided.
- Inspect the Bulb Socket: Look inside the socket where the bulb connects. It should be clean and metallic. Avoid any assembly that shows signs of heavy corrosion, rust, or melted plastic, as the wiring is likely compromised.
- Verify the Pigtail and Connector: If the lamp comes with a wiring pigtail, check that the connector is intact, not cracked, and that the wires aren't brittle or cut.
Replacement Overview & Difficulty
Replacing the rear side marker lamp on a 1990 Buick Regal is a straightforward job suitable for any DIYer.
- Difficulty Rating: 1 out of 5
- Estimated Time: 15-30 minutes
- Tools Needed: Basic hand tools (likely a small socket set or nut driver).
The replacement process typically involves accessing the back of the lamp from inside the trunk. You may need to pull back the trunk liner to expose the nuts or clips holding the assembly in place. Once the fasteners are removed, the old lamp can be pushed out from the vehicle body, the electrical connector unplugged, and the new lamp installed by reversing the steps.
Cost Comparison for Replacement
The cost to replace a rear side marker lamp varies depending on whether you do it yourself or hire a shop, and which parts are needed.
| Part/Service | Estimated Cost | Notes |
|---|---|---|
| New OEM Assembly | N/A | These parts are generally discontinued and no longer available from GM dealers. |
| New Aftermarket Assembly | $20 - $50 (if available) | Complete aftermarket assemblies for this specific model are very rare. Most available parts are just bulbs or sockets. |
| Used OEM Assembly | $25 - $75 | The most common option. Price depends on condition and seller. |
| Replacement Bulb Only | $5 - $15 | Commonly available at any auto parts store. |
| Shop Labor | $50 - $100 | Typically 0.5 to 1 hour of labor. |
Frequently Asked Questions (FAQ)
Is it illegal to drive with a broken rear side marker light?
Yes. Side marker lights are required safety equipment under federal motor vehicle safety standards. While a non-working side marker may not get you pulled over as quickly as a failed headlight or brake light, it can result in a "fix-it" ticket and will cause your vehicle to fail a safety inspection.
My light is still out after changing the bulb. What's wrong?
If a new bulb doesn't fix the problem, the issue is electrical. The most likely culprit is corrosion in the bulb socket. Clean the metal contacts inside the socket thoroughly. If that doesn't work, use a multimeter to check for power at the connector and for a good ground connection. The problem could also be a blown fuse or a break in the wiring.
What bulb does the 1990 Regal rear side marker use?
Common bulb types for this era include the 2057 or similar miniature bulbs. However, the best way to be certain is to remove the old bulb and match the number printed on its base. You can also consult your owner's manual or an auto parts store's fitment guide.
Are the left and right rear side markers the same part?
No, the left (driver-side) and right (passenger-side) rear side marker lamps are not interchangeable. They are mirror images of each other, shaped to fit the specific contour of the car's body on each side. Ensure you are purchasing the correct side for your needs.
Technical Specifications
OEM Part Numbers: 16506142 16506144 16506113 16508311
Bulb Type: Varies, typically a miniature incandescent bulb like a 2057. Verify by checking the old bulb. Lens Color: Red.
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.
- Buick Regal: