Infiniti G35 (2003-2008) Brake Light Switch: A Guide to Replacement
If your G35 won't start, shift out of park, or has brake lights acting up, this guide is for you.
- Before buying a new switch, check for broken plastic pieces on your floor mat; the brake pedal stopper is a common failure point on the G35.
- A faulty switch can prevent your car from starting or shifting out of park, in addition to causing brake light issues.
- Replacement is a simple DIY job that takes less than 30 minutes and requires no special tools.
- A recall was issued for the 2003 model year, highlighting that this part has a known history of failure.
A Common Problem: Check This Before You Buy
Before you replace the brake light switch, check your driver-side floor mat. Look for small, broken pieces of plastic. A very common failure on the 2003-2008 G35 is not the switch itself, but a small plastic stopper on the brake pedal arm. This stopper presses the switch's plunger when the pedal is released. Over time, the plastic becomes brittle and disintegrates. When it breaks, the plunger goes through the hole where the stopper used to be, and the switch thinks the brake pedal is always pressed. This can cause the brake lights to stay on and drain your battery.
Symptoms of a Failing Brake Light Switch
When the brake light switch itself fails, it can cause a number of issues. Because it's connected to several different systems, a bad switch can be confusing to diagnose. Common symptoms include:
- Brake Lights Don't Work: The most obvious and dangerous symptom. The switch fails to complete the circuit, and your brake lights never turn on.
- Brake Lights Stay On: The switch can fail in the 'on' position, keeping your brake lights illuminated constantly and draining the battery.
- Cannot Shift Out of Park: The automatic transmission requires a signal from the brake switch to allow the shifter to move out of Park. If this signal isn't sent, you'll be stuck. 🎬 See how to troubleshoot a shifter stuck in Park.
- Cruise Control Inoperable: The cruise control system uses the switch to disengage. If the switch is faulty, cruise control may not set or may turn off unexpectedly.
- ABS / VDC / SLIP Lights On: These stability systems rely on input from the brake switch. A bad signal can cause warning lights to appear on your dashboard.
Choosing the Right Aftermarket Part
While an OEM switch from Infiniti is always an option, the aftermarket offers several quality choices that can save you money. These brands are known to provide reliable parts for your G35.
Premium Aftermarket Brands:
- Standard Motor Products (Standard / SMP): A well-respected brand known for producing high-quality electronic components that often meet or exceed OEM specifications. They are a trusted choice for professional mechanics.
- Beck Arnley: This brand specializes in sourcing parts that match the original equipment in form, fit, and function, making them a reliable alternative to the dealer part.
Standard & Value Brands:
- Dorman: Dorman is a popular brand known for its wide availability and affordable prices. They often create "OE Solutions" parts that can sometimes improve on the original design. While quality can sometimes be inconsistent across their vast catalog, their switches are a common and viable repair option.
- Facet, Holstein, URO Parts, Vemo, etc.: These brands offer a budget-friendly alternative. They can be a good choice if cost is your primary concern, but may not have the same reputation for longevity as premium brands.
Cost Comparison (2003-2008 Infiniti G35)
| Part Type | Estimated Cost |
|---|---|
| New OEM | $35 - $75 |
| New Aftermarket | $24 - $68 |
| Shop Labor | $60 - $120 |
Known Issues & Recalls
Frequently Asked Questions (FAQ)
Can I replace the G35 brake light switch myself?
Yes, this is a very DIY-friendly repair. The switch is located above the brake pedal and is typically removed by disconnecting the wiring and twisting the switch housing. 🎬 Watch a step-by-step brake light switch replacement walkthrough. No special tools are required, and the job can usually be done in less than 30 minutes.
Why are my brake lights stuck on and draining my battery?
This is a classic symptom for the G35. First, check for broken plastic pieces from the brake pedal stopper on your floor mat. If the stopper has disintegrated, the switch is not being pressed, and the car thinks the brakes are on. If the stopper is intact, the switch has likely failed internally in the 'on' position and needs to be replaced.
Why won't my G35 shift out of Park?
For safety, your car requires a signal that the brake pedal is pressed before it allows the shifter to move out of Park. A faulty brake light switch prevents this signal from being sent, locking your shifter.
There are two switches on the brake pedal. Which one is it?
Your G35 has two switches on the brake pedal assembly. The brake light switch is the one with a four-pin electrical connector. The other switch, which has a two-pin connector, is for the cruise control release.
Helpful Videos
Technical Specifications
OEM Part Numbers: 25320-AX00E 25320-AX00C 25320-AX00B 25320-AX00A 25320-AX000 25320-JN00A
Located on the brake pedal support, the correct switch has a 4-pin electrical connector.
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.
- INFINITI G35: