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Toyota MR2 Brake Light Switch Guide for 1985-1995 Models

Understanding brake light switch failure and replacement for your AW11 or SW20 MR2.

4 minutes to read 1985-1995 Toyota MR2
Difficulty
1/5
Est. Time
0.5 hrs
DIY Doable?
✅ Yes
Shop Labor
$50-$100
Used OEM Price
$10-$25
🚫 Do not drive — Driving with non-functional brake lights is illegal and extremely dangerous to you and other drivers.
Key Takeaways
  • If your brake lights are stuck on, first check for a broken plastic stopper on the brake pedal arm before buying a new switch.
  • Verify if your MR2 has cruise control before ordering, as it determines whether you need a 2-pin or 4-pin switch.
  • A faulty brake light switch is a critical safety issue; do not drive the vehicle if the brake lights are not functioning correctly.
  • Replacement is simple for a DIY mechanic, mainly requiring a 14mm wrench and tolerance for working in a tight footwell.
The brake light switch on your Toyota MR2 is a small but critical sensor located on the brake pedal assembly. Its main job is to tell the car's electrical system when you are pressing the brake pedal. When you press the pedal, the switch closes an electrical circuit, sending power to your brake lights. For MR2 models equipped with cruise control, the switch also has a second function: it immediately deactivates the cruise control system the moment you touch the brakes. It can also be connected to the automatic transmission's shift interlock, preventing you from shifting out of "Park" unless the brake is applied.

Symptoms of a Failing Brake Light Switch

A bad brake light switch can cause several noticeable and potentially dangerous problems. Because this part is essential for safety, you should address these symptoms immediately.

Safety Warning: Do Not Drive

If your brake lights are not working or are stuck on, your car is not safe to drive. It is illegal and dramatically increases the risk of a rear-end collision. Have the vehicle inspected and repaired before driving.

Brake Lights Don't Work

The most serious symptom is when your brake lights fail to illuminate when you press the brake pedal. Before blaming the switch, it's wise to first check the brake light fuse and the bulbs themselves.

🎬 Watch: A quick guide on how to test the switch.

Brake Lights Stay On

Conversely, the switch can fail in a way that causes the brake lights to remain on even when you're not touching the pedal. This will drain your battery. Often, this issue on older Toyotas isn't the switch itself, but a small, brittle plastic pad on the brake pedal arm that has disintegrated. This pad is meant to press the switch's plunger when the pedal is at rest. When it breaks, the plunger is no longer pressed, and the car thinks the brakes are always being applied. Look for small, broken plastic bits on your driver-side floor mat.

🎬 Watch: How to fix brake lights that won't turn off.

Cruise Control Issues

If your MR2 has cruise control, a faulty brake light switch can prevent the system from engaging. The cruise control system needs to see a functioning brake switch before it will activate.

Choosing the Right Aftermarket Switch

For a vehicle like the 1985-1995 MR2, both OEM and quality aftermarket brake light switches are viable options. The original Toyota parts are known for their longevity, but a good aftermarket part can offer similar performance for a lower price.

The brands available in our inventory include:

  • Standard Ignition (SMP): A widely respected aftermarket manufacturer known for producing parts that meet or exceed OEM specifications. They are generally considered a reliable choice for electrical components like switches.
  • Facet: Often seen as a budget-friendly option, with some sources indicating it as an OE-equivalent from Italy.
  • Rostra Powertrain: A known manufacturer of various automotive electrical products.

Given the low cost of this part, a quality aftermarket brand like Standard Ignition is a solid choice. However, if the price difference is minimal, a genuine Toyota part provides the most peace of mind. The most critical factor is ensuring you buy the correct switch for your car's options.

Check for Cruise Control

MR2s without cruise control use a simple 2-pin switch. Models with cruise control use a 4-pin switch to handle both the brake light and cruise-disable functions. Ordering the wrong one will result in either the part not fitting or the cruise control not working. Always verify which system your car has before ordering.

Cost of Replacing a Toyota MR2 Brake Light Switch

Part Type Estimated Cost
New Aftermarket $15 - $56
New OEM (Genuine Toyota) $30 - $85
Shop Labor $50 - $100

Cost estimates are approximate and can vary based on location and supplier.

Frequently Asked Questions (FAQ)

My brake lights are stuck on. Is it the switch?

It might be, but first, check for a broken plastic stopper pad on the brake pedal arm. This is a very common failure on older Toyotas. You will likely find the broken pieces on your floor mat. Replacing this small, inexpensive pad (Toyota P/N 90541-06036) often solves the problem without needing to replace the entire switch.

Can I replace the MR2 brake light switch myself?

Yes, this is a very DIY-friendly job. The main challenge is the awkward position required to work under the dashboard. The switch is located high on the brake pedal assembly. It is held in place by a locknut (usually 14mm) and simply threads in and out.

🎬 See this walkthrough on replacing the switch yourself.
Is there a recall on the MR2 brake light switch?

No. While Toyota has issued recalls for brake light switches on other models, there are no active recalls or widespread TSBs for this part on the 1985-1995 Toyota MR2.

Are the switches for the AW11 and SW20 MR2 the same?

No, they often use different part numbers. The AW11 (1985-89) and SW20 (1990-95) generations may have different switch designs. It is essential to order the part specific to your vehicle's year and options (especially cruise control) to ensure proper fit and function.

Easy Fix For Brake Lights That Stay On! || Toyota MR2(sw20)!
Easy Fix For Brake Lights That Stay On! || Toyota MR2(sw20)!
How to replace Brake Light Switch in brake pedal Toyota cars
How to replace Brake Light Switch in brake pedal Toyota cars
1990 Toyota brake light switch pad
1990 Toyota brake light switch pad
How to Test a Brake Light Switch.
How to Test a Brake Light Switch.

Technical Specifications

OEM Part Numbers: 84340-12020 84340-22071 84340-22072 84340-32050 84340-32090 84340-30070

Threaded body with a plunger mechanism. Available in 2-pin (no cruise control) and 4-pin (with cruise control) configurations.

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:
  • Toyota MR2: 19851986198719881989199019911992199319941995
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