Brake Light Switch Guide for the 1940-1949 Buick Super Series 50
Keep your classic Buick safe and its brake lights reliable with the right replacement switch.
- The switch is a hydraulic unit on the master cylinder or brake line, not on the pedal.
- Failure is a critical safety issue; if your brake lights don't work, replace the switch immediately.
- Aftermarket brands like Standard Ignition and Rostra are your primary options.
- Replacement requires bleeding the brakes, a crucial step for safety.
Is Your Brake Light Switch Failing?
A bad brake light switch is a critical safety problem. Because it relies on hydraulic pressure, it can fail without much warning. If you notice any of these signs, it's time to inspect the switch.
| Symptom | Description | Severity |
|---|---|---|
| Brake Lights Don't Work | This is the most common and dangerous sign. The switch no longer completes the circuit when you press the brakes. | Critical |
| Brake Lights Stay On | Less common, but the switch can get stuck in the 'on' position. This will drain your battery and confuse other drivers. | Moderate |
| Delayed or Flickering Lights | The lights may only come on after a very hard press of the brake pedal, or they might flicker. This indicates the switch is wearing out internally. | Serious |
Choosing the Right Aftermarket Switch
For a classic vehicle like the Buick Super, finding original new parts from GM is no longer possible. Your choice is between a modern aftermarket part and a potentially expensive New Old Stock (NOS) part. For a simple and critical component like a brake light switch, a new aftermarket part is the most practical and reliable choice.
Two common brands you will find are:
- Standard Ignition (Standard Motor Products): A very well-known aftermarket brand that has been around since 1919. Their SLS-27 switch is a common replacement for this vehicle. While widely available, some classic car owners have reported mixed reliability with modern hydraulic switches, with some failing prematurely. One product document warns against using these switches with silicone brake fluid.
- Rostra Powertrain: Rostra produces parts for both original equipment and the aftermarket. They promote their use of quality materials like copper alloy conductors and 100% performance testing.
Pro Tip: Check Your Connectors! Original switches on these Buicks used screw-on terminals for the wires. Some modern replacements use push-on or bullet-style connectors. Check the switch you are buying and be prepared to install new wire ends if they don't match your car's wiring.
Typical Replacement Costs
The cost for a new aftermarket brake light switch is very affordable. The main cost consideration is the labor, especially if you are not comfortable bleeding the brake system yourself.
| Part Type | Estimated Cost |
|---|---|
| New Aftermarket Switch | $10.92 - $15.52 |
| Shop Labor | $50 - $100 |
Installation Requires Brake Bleeding
Replacing this switch involves opening the sealed hydraulic brake system. This will let air into the brake lines. After installing the new switch, you must bleed the brakes to remove all air. Air in the brake lines will cause a spongy pedal and a dangerous loss of braking power. If you are not experienced with bleeding brakes, this job should be left to a qualified mechanic.
Frequently Asked Questions
Where is the brake light switch located on my Buick Super?
Do not look for the switch by the brake pedal. On these cars, it is located under the hood, screwed into the master cylinder or a brake line distribution block on the frame.
Why do my brake lights only work when I press the pedal very hard?
This is a classic symptom of a failing hydraulic switch. The internal diaphragm has likely become stiff with age and requires much more pressure to activate. A new switch should fix this problem.
Will a new switch fix my dim brake lights?
Probably not. The brake light switch is an on/off device. Dim lights are almost always caused by a poor ground connection at the tail light housings, corrosion in the bulb sockets, or other wiring issues in the lighting circuit.
Are there any recalls for the brake light switch on a 1940-1949 Buick?
No. There are no recalls or Technical Service Bulletins (TSBs) for this part on your vehicle. The modern NHTSA recall system was not in place for vehicles of this era.
Technical Specifications
Hydraulic Pressure Activated, 2-Terminal, 1/8" NPT Fitting
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.