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2000-2005 Buick Century Brake Light Switch: A Comprehensive Guide

Understanding the common failures and replacement options for the brake light switch in your Buick Century.

3 minutes to read 2000-2005 Buick Century
Difficulty
2/5
Est. Time
0.5 hrs
DIY Doable?
✅ Yes
Shop Labor
$85-$125
🚫 Do not drive — No, you should not drive if your brake lights are not working as it is a major safety hazard.
Key Takeaways
  • A faulty brake light switch is a critical safety issue; replace it immediately if your brake lights are not working.
  • Symptoms are not limited to the brake lights; a bad switch can also cause the cruise control to fail and the shifter to get stuck in Park.
  • This is an inexpensive and simple repair, making it a good DIY project for most owners.
  • Choose a new part from a reputable brand like ACDelco, Standard Ignition, or Rostra for a reliable repair.
The brake light switch on your 2000-2005 Buick Century is more than just a simple switch for your brake lights. It is a critical component located on the brake pedal assembly. When you press the brake pedal, this switch completes an electrical circuit to turn on the brake lights, signaling to drivers behind you that you are slowing down. It also sends a signal to other important systems in your car. This includes disengaging the cruise control, and allowing the automatic transmission to shift out of Park via the shift interlock safety feature.

Is a Failing Brake Light Switch a Serious Problem?

Yes, a faulty brake light switch is a serious safety issue. If it fails, your brake lights may not turn on, which is extremely dangerous because drivers behind you won't know you are stopping. This significantly increases the risk of a rear-end collision. Other symptoms, like being unable to shift out of Park, can leave you stranded. Because this part is inexpensive and critical for safety, it should be replaced as soon as you notice any symptoms.

Immediate Action Required

A failing brake light switch can prevent your brake lights from working. Do not drive your vehicle if you have confirmed the brake lights are not functioning. It is a major safety hazard and illegal.

Choosing the Right Aftermarket Brake Light Switch

For the 2000-2005 Buick Century, the brake light switch is a relatively simple and reliable part. While the original equipment (OEM) ACDelco part is always a safe bet, quality aftermarket options provide excellent value. The key is to choose a reputable brand.

  • OEM (ACDelco): The original part for your Buick is made by ACDelco, GM's official parts brand. It guarantees a perfect fit and function. If the price difference is minimal, choosing the OEM part provides peace of mind.
  • Standard Ignition (Standard Motor Products/SMP): Standard is a well-regarded aftermarket manufacturer with a long history. They are known for producing quality electronic components that are often considered a reliable alternative to OEM parts. Many professional mechanics use Standard parts. Just be sure to avoid their budget "T-Series" line if possible, as the quality can be inconsistent.
  • Rostra Powertrain: Rostra specializes in electronic components and is an OE supplier for some manufacturers. They are known for quality transmission parts, including sensors and switches. A Rostra switch is a solid choice, known for good engineering and durability.

Pro Tip: Given the low cost of this part, there is little reason to consider a used switch. The internal contacts wear out over time, so a new switch from a reputable brand is the best and safest option.

Estimated Replacement Costs

The cost to replace a brake light switch is very reasonable. The part itself is affordable, and the labor time is short.

Part/ServiceEstimated Cost
New Aftermarket Part$21.77 - $42.37
Shop Labor$85 - $125
Total Professional Replacement$102 - $149

Frequently Asked Questions (FAQ)

Can I replace the brake light switch myself?

Yes, this is a very DIY-friendly repair for most home mechanics. The switch is located above the brake pedal and is usually held in place by a clip or by being threaded into a bracket. The job requires working in a tight space under the dashboard but typically only requires basic hand tools. The process involves disconnecting the electrical connector, removing the old switch, and installing the new one.

🎬 See this step-by-step guide for replacing a Buick brake pedal switch.
Why did my cruise control stop working?

The cruise control system relies on the brake light switch to know when to disengage. If the switch is faulty, it may send a constant or intermittent "brake on" signal, which will prevent the cruise control from setting or cause it to cancel unexpectedly. This is one of the most common symptoms of a failing brake light switch on this vehicle.

Why am I stuck in Park?

Modern cars have a safety feature called a shift interlock that prevents you from shifting out of Park unless your foot is on the brake. The brake light switch is what sends the signal to release this lock. If the switch fails, the car doesn't know you are pressing the brake, and the shifter will remain locked in Park.

My brake lights work, but I have other symptoms. Could it still be the switch? 🎬 Watch: How to test and replace a faulty brake light sensor.

Yes. The brake light switch often has multiple electrical contacts inside for its different functions (brake lights, cruise control, shift interlock). It is possible for one set of contacts to fail while another continues to work. For example, the contacts for the cruise control could fail, but the ones for the brake lights might still be good.

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Technical Specifications

OEM Part Numbers: 25668878 D888A

Located on the brake pedal support bracket. Typically a plastic body with a plunger and an electrical connector.

Wrenchy
Article researched & written by
Go-Parts' AI research assistant. Every article is backed by live web research, verified OEM data, and real technician knowledge — so you get accurate, up-to-date information you can trust.
Meet Wrenchy → Updated Apr 19, 2026

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.

Year Coverage
This article covers the Brake Light Switch for:
  • Buick Century: 200020012002200320042005
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