2014-2018 Bentley Flying Spur High Mount Stop Lamp: Failures and Fitment Warnings
This guide covers the common failure symptoms, complex replacement, and critical part number information for the third brake light on the 2014-2018 Bentley Flying Spur.
- A critical fitment warning exists: the part may differ for vehicles with standard vs. optional privacy rear glass. You must verify compatibility before buying.
- Common OEM part numbers for the standard glass version are 3W5945399F and 3W5945399L.
- Failure is typically due to internal electronics or LED burnout in the sealed unit, often presenting as an intermittent fault before failing completely.
- Replacement is a difficult (4/5) and labor-intensive job requiring removal of the rear seats and interior trim panels, making professional installation highly recommended.
Symptoms of a Failing High Mount Stop Lamp
Failure of the third brake light on a 2014-2018 Bentley Flying Spur can be intermittent at first, but typically becomes a permanent fault. Because it is a sealed LED unit, individual bulbs cannot be replaced.
- "Check Third Brake Lamp" Warning: The most common symptom is a warning message appearing on the instrument cluster. This indicates the vehicle's body control module has detected a problem with the light's circuit.
- Intermittent Operation: The light may work sporadically, sometimes fixing itself while driving before failing again later. This can be an early sign of a failing internal circuit board, a loose connection, or the beginning of water intrusion.
- Complete Failure: The light does not illuminate at all when the brake pedal is pressed. This is a permanent failure and a safety hazard that makes the vehicle illegal to operate in most jurisdictions.
- Partial Failure or Flickering: Only some of the LEDs within the strip may light up, or the light may flicker dimly. This points to failure of the internal LED drivers or corrosion on the circuit board.
Pro Tip: In some cases, intermittent failure that worsens after rain can be caused by corrosion on the light's internal electrical connector. While the unit is sealed, some owners have had success carefully cutting the housing open, cleaning the corroded contacts, and resealing the unit. This is a delicate procedure that risks destroying the lamp but may be an alternative to a costly replacement.
Known Issues, Recalls, and TSBs
As of this writing, there are no official recalls or Technical Service Bulletins (TSBs) issued by Bentley or the National Highway Traffic Safety Administration (NHTSA) for widespread failure of the high mounted stop lamp on the 2014-2018 Flying Spur. Failures appear to be isolated incidents due to age, moisture, or electronic component failure within the sealed lamp assembly.
Buying a Used High Mount Stop Lamp: The Definitive Checklist
Due to the high cost of a new OEM unit, a recycled part is an excellent value. However, careful inspection is critical to ensure you get a functional and compatible part.
Warning: Fitment may depend on the type of rear window glass. The known OEM part numbers are for vehicles with the standard tint rear screen. It is reported that models with optional factory privacy glass may require a different part number. This distinction is not clearly noted in most public parts catalogs, so visually comparing a potential replacement to your original part is the most reliable way to ensure compatibility.
What to Check Before You Buy:
- Verify the Part Number: The most common OEM part numbers for the standard-glass version are 3W5945399F and its successor, 3W5945399L. Ensure the part you are buying matches one of these numbers. Part number 3W5945399L is noted to supersede 3W5945097D.
- Inspect the Lens: Look for any cracks, deep scratches, or signs of hazing on the red plastic lens. A crack can allow moisture to enter, leading to premature failure.
- Examine the Seal: Check the condition of the foam or rubber seal around the housing. A compressed, brittle, or crumbling seal will not prevent water from leaking into the vehicle's cabin or the light's electronics.
- Check for Water Damage: Look for any signs of moisture, fogging, or a white, chalky residue inside the lens. This is a clear indicator of a failed seal and potential electronic damage.
- Test if Possible: If you can, ask the seller to test the light with a 12V power source. Ensure all LEDs across the entire strip illuminate brightly and evenly.
Why Used OEM is the Best Choice
For a vehicle like the Flying Spur, a used OEM (Original Equipment Manufacturer) part is almost always superior to other options. New aftermarket replacements for this specific part are generally not available. You may find kits online that consist of a resistor designed to trick the car's computer and turn off the dashboard warning light, but these do not fix the light itself and leave the safety feature non-functional. A used OEM lamp ensures perfect fitment, correct electrical connections, and the material quality expected of a Bentley.
Replacement Overview & Difficulty
Replacing the high mount stop lamp on a 2014-2018 Flying Spur is a complex task that requires extensive disassembly of the rear interior.
- Difficulty Rating: 4 out of 5 (Difficult)
- Primary Steps: The process involves removing the rear seat bottom cushion, the rear seat back, 🎬 Watch: How to remove the rear seat and panels the upper D-pillar trim covers, 🎬 See this guide on removing the rear headliner and trim and the rear parcel shelf to gain access to the lamp's wiring and mounting points from inside the car.
- DIY Feasibility: This job is recommended for experienced DIY mechanics or professional technicians only. The risk of damaging the expensive and delicate interior trim panels is high. The procedure requires patience and care.
Warning: Some early models of the related Bentley Continental GT required the rear windscreen to be removed for this repair. While later service procedures for the Flying Spur avoid this, it highlights the integrated nature of the part. Be aware that some original lamps may have a retaining lip that makes removal from the outside impossible without breaking the lamp, forcing the replacement to be done from inside.
Cost Comparison
The cost to replace a Flying Spur high mount stop lamp varies significantly between new and used parts. Labor is a major factor due to the complexity of the job.
| Part Source | Estimated Cost |
|---|---|
| New OEM | $880 - $1,670 |
| New Aftermarket | Not Available |
| Used OEM | $135 - $350 |
| Shop Labor | $350 - $750 |
Frequently Asked Questions (FAQ)
Can I just replace the burnt-out LEDs in my brake light?
No, the high mount stop lamp is a fully sealed unit. The LEDs are soldered to an internal circuit board and are not designed to be serviced individually. Attempting to open the unit will likely damage it, though some have succeeded in repairing internal corrosion. The standard repair is to replace the entire lamp assembly.
How do I know if my Flying Spur has standard or privacy rear glass?
Factory privacy glass is significantly darker than the standard tinted glass and is most noticeable on the rear passenger and back windows. If you are unsure, you can contact a Bentley dealership with your Vehicle Identification Number (VIN) to get the vehicle's original build sheet, which will list optional features like privacy glass. Given the uncertainty, the safest method is to visually compare your existing lamp to any potential replacement before purchasing.
Is it illegal to drive with a broken third brake light?
Yes. High mounted stop lamps have been mandatory on passenger cars in the United States since 1986. Driving with a non-functional third brake light is a safety violation that can result in a traffic ticket and will cause your vehicle to fail a safety inspection.
My warning light is on, but the brake light still works. What's wrong?
This could be an intermittent fault, which is common as the unit begins to fail. The vehicle's computer may detect a momentary voltage drop or resistance change that is not yet a permanent failure. It could also indicate a problem with the wiring or a loose connection. In either case, it is a sign that the component should be inspected before it fails completely.
Helpful Videos
Technical Specifications
OEM Part Numbers: 3W5945399F 3W5945399L 3W5945097D
Sealed LED unit. Connects to vehicle CAN bus system for fault monitoring.
We Have This Part in Stock
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.
- Bentley Flying Spur:
- 🎬 Helpful Videos
- 🛍️ Shop This Part
- Symptoms of a Failing High Mount Stop Lamp
- Known Issues, Recalls, and TSBs
- Buying a Used High Mount Stop Lamp: The Definitive Checklist
- What to Check Before You Buy:
- Why Used OEM is the Best Choice
- Replacement Overview & Difficulty
- Cost Comparison
- Frequently Asked Questions (FAQ)
- 🎟️ Get 5% Off