GMC P35 Brake Light Switch Guide for 1975-1978 Models
Keep your classic P35 safe and legal by ensuring your brake lights work every time.
- The brake light switch is a critical safety part; if your brake lights don't work, replace the switch immediately.
- For this vehicle, Standard Ignition is a well-regarded aftermarket brand, while Skyward is a budget-friendly alternative.
- Replacement is a simple DIY task requiring only basic tools and about 30 minutes.
- There are no recalls for the service brake light switch, but always check fuses and bulbs before and after replacement.
Is Your Brake Light Switch Failing?
A bad brake light switch on your P35 has very clear symptoms. Because this is a simple, mechanical part, troubleshooting is straightforward. If you notice any of these issues, your switch is likely the problem.
- Brake Lights Don't Turn On: This is the most dangerous symptom. If the switch fails in the 'open' position, it never sends power to the lights.
- Brake Lights Stay On: If the switch gets stuck in the 'closed' position, it will continuously send power to the brake lights, even when your foot is off the pedal. This can drain your battery and confuse other drivers.
- Flickering Brake Lights: An intermittent connection inside a worn-out switch can cause the brake lights to flicker when you press the pedal or when driving over bumps.
Safety and Legal Warning
Driving without functional brake lights is a major safety hazard and is illegal in all states. If your brake lights are not working, the vehicle is not safe to drive. A faulty switch should be replaced immediately.
Choosing the Right Aftermarket Switch
For a vintage vehicle like the 1975-1978 P35, finding original OEM parts is nearly impossible. Aftermarket parts are your primary option. The quality can vary, so it's important to understand the brands available.
- Standard Motor Products (Standard Ignition): Standard is a well-known and respected aftermarket brand that has been around for a very long time. Their parts are generally considered to be of good quality, often meeting or exceeding original specifications. For a critical safety part like a brake light switch, this is a reliable choice.
- Skyward: Skyward is a brand typically associated with more budget-friendly pricing. While it may function correctly, it may not have the same long-term durability or rigorous testing as a more established brand like Standard Ignition. For a part that is easy to access and inexpensive, it can be a viable option if budget is the main concern.
Pro Tip: Check Your Wiring
On older vehicles, wiring can become brittle. When replacing the switch, inspect the connector and wires. If they look cracked or corroded, consider replacing the connector pigtail at the same time to ensure a solid connection.
Brake Light Switch Cost for 1975-1978 GMC P35
| Part Type | Price Range | Notes |
|---|---|---|
| New Aftermarket | $5.40 - $29.97 | Price depends on the brand. Standard Ignition is typically priced higher than budget brands. |
| Shop Labor | $50 - $100 | This is a quick job, typically taking less than 30 minutes. Labor cost depends on the shop's hourly rate. |
Frequently Asked Questions (FAQ)
Is replacing the brake light switch a DIY job?
Yes, this is a very easy job for a DIYer. The switch is located on the brake pedal support bracket under the dashboard. It's usually held in by a small clip or a single bolt and is easy to access, though it may require lying on your back in the footwell. The process involves disconnecting the electrical connector, removing the old switch, installing the new one, and reconnecting the power.
Are there any recalls for the brake light switch on my P35?
No, there are no specific recalls for the brake light switch on the 1975-1978 GMC P35. There was a recall in 1978 for the parking brake indicator light switch wiring on some P35 models, but this is a separate part and issue.
My brake lights don't work, but the switch is new. What else could it be?
If a new switch doesn't solve the problem, check the basics first: the fuse for the stop lamps in your fuse panel and the brake light bulbs themselves. On these GM trucks, the brake light signal also passes through the turn signal switch in the steering column. A faulty turn signal switch can sometimes prevent the brake lights from working correctly.
Do I need a special tool to replace this switch?
No special tools are required. Basic hand tools like a screwdriver or a small socket set are usually all that is needed to remove the retaining clip or bolt.
Technical Specifications
Mechanically activated switch mounted to the brake pedal assembly. Typically features a 2-terminal 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.