1937-1939 Nash Ambassador Brake Light Switch Guide
Keeping the brake lights on your classic Nash working is a critical safety task.
- The brake light switch on a '37-'39 Nash is a hydraulic pressure switch, not a mechanical one.
- Failure is a critical safety issue; do not drive if your brake lights are not working.
- A new aftermarket switch from a brand like Standard Ignition is the most reliable and practical option.
- Replacing the switch requires bleeding the brake system, a crucial step for safety.
Symptoms of a Failing Brake Light Switch
Diagnosing a bad brake light switch on a vintage car like the Nash Ambassador is usually straightforward. The problems are almost always the same. Look for these two main symptoms:
- Brake Lights Don't Turn On: This is the most common and most dangerous symptom. Before blaming the switch, always check the bulbs and the fuse first. If those are good, the switch is the next likely culprit.
- Brake Lights Stay On: Less common, but it can happen. The switch can get stuck in the "on" position, leaving your brake lights permanently illuminated. This will drain your battery and confuse drivers behind you.
Safety First
A faulty brake light switch is a critical safety issue. If your brake lights are not working, you should not drive the vehicle until it is repaired. The risk of a rear-end collision is extremely high.
Choosing the Right Aftermarket Part
For a 1937-1939 Nash Ambassador, finding a "New Old Stock" (NOS) or original equipment (OEM) brake light switch is nearly impossible. Even if you found one, an 80-year-old part may not be reliable. A new aftermarket switch is the most practical and safest choice.
Standard Ignition (SMP): The available aftermarket brand, Standard Ignition, is a well-established company with a long history of producing quality replacement parts for a huge range of vehicles, including classics. Their switches are manufactured to meet or exceed the original performance, often using modern materials like high-impact composite housings and copper alloy conductors for better durability and electrical performance. For a classic like the Ambassador, a new Standard switch is a reliable choice.
Pro Tip: Some owners of classic cars with hydraulic pressure switches report that new switches can sometimes require a lot of pedal pressure to activate. While a quality new switch should work correctly, some enthusiasts have modified their systems to use a modern mechanical switch at the brake pedal for a more immediate response. 🎬 Watch how to install a mechanical brake light switch upgrade. However, for a stock restoration, a new hydraulic switch from a reputable brand is the correct path.
Replacement Cost
Replacing the brake light switch is a relatively inexpensive job. The primary cost is the part itself, with labor being minimal for a professional mechanic familiar with vintage cars.
| Item | Estimated Cost |
|---|---|
| New Aftermarket Switch | $38.97 |
| Shop Labor | $50 - $100 |
| Total Estimated Cost | $88.97 - $138.97 |
Cost estimates are for reference only and may vary based on your location and the specific rates of your repair shop.
Frequently Asked Questions
Is this a difficult part to replace myself?
For a DIY mechanic, this is a relatively easy job. It involves unscrewing the old switch, screwing in the new one, and connecting the two wires. However, because it's part of the hydraulic brake system, you will introduce air into the lines. You MUST bleed the brakes after replacing the switch to ensure your brakes work safely. If you are not comfortable bleeding brakes, leave this job to a professional.
Do I need a special switch for a 6-volt system?
Most simple pressure switches like this are not voltage-specific. They are a simple on/off contact and will work with both 6-volt and 12-volt systems. The switch's job is just to complete the circuit, regardless of the voltage.
Why did my new switch fail so quickly?
While unlikely with a quality part, premature failure can happen. Some owners of classic cars have noted that modern silicone brake fluid (DOT 5) can sometimes cause issues with the internal components of reproduction switches. If you are using silicone fluid, ensure the switch is compatible. Most owners, however, have no issues.
Are there any recalls for the brake light switch?
No. Formal recalls and the NHTSA (National Highway Traffic Safety Administration) did not exist when the 1937-1939 Nash Ambassador was built. There are no official recalls or Technical Service Bulletins (TSBs) for this part on this vehicle.
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Technical Specifications
Hydraulic Pressure Activated, 2-Terminal
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.