1967 GMC LI3500 Headlight Switch: Symptoms and Replacement Guide
If your headlights flicker, dim, or fail, the switch is the likely culprit on your classic GMC truck.
- A failing headlight switch is a common and serious issue; symptoms include flickering lights or a hot switch.
- Ensure you buy the correct 8-pin switch specifically for a 1967 model; later years used a 7-pin switch with different functionality.
- Replacement is a straightforward DIY task that requires basic tools and about 30 minutes.
- For long-term reliability, especially with original wiring, choosing a premium brand like Standard Ignition is recommended.
Is Your Headlight Switch Failing? Common Symptoms
The headlight switch on a classic GMC truck handles significant electrical loads, making it a frequent failure point. Over time, internal components corrode or wear out, leading to noticeable problems. Watch for these signs.
| Symptom | Description | Severity |
|---|---|---|
| Flickering or Intermittent Lights | Headlights, taillights, or dash lights cutting in and out is a classic sign of a worn or corroded internal contact in the switch. The switch contains a built-in circuit breaker that will cycle the lights if it overheats from high resistance or a short. | Serious |
| Switch is Hot to the Touch | A switch that feels warm or hot is a major warning sign. This indicates high electrical resistance, which can melt the switch, its connector, or nearby wiring, creating a fire risk. | Critical |
| Lights Don't Turn On or Off | You may find that only the parking lights work while the headlights don't, or you can't turn the lights off at all. This points to a complete failure inside the switch mechanism. | Serious |
| Dash Lights or Dome Light Issues | The rotating part of the switch (a rheostat) that dims the dash lights can fail, leaving you with no dash illumination. Similarly, the dome light function may stop working. | Minor |
Choosing the Right Aftermarket Headlight Switch
For a 1967 GMC LI3500, new OEM switches are no longer available. You will be choosing between different aftermarket brands. It is critical to get the correct switch for your specific model year.
Pro Tip: The 1967 GMC truck uses a specific 8-pin headlight switch. Later models from 1968-1972 used a 7-pin switch. A unique feature of the 1967 8-pin switch is that it turns the front parking lights off when the headlights are turned on. Using the wrong switch will cause your lights to function incorrectly.
Brand Tiers
- Standard Ignition (SMP): Often considered a higher-quality aftermarket brand, Standard Ignition provides parts that are designed to meet or exceed original specifications. For a critical component like a headlight switch that handles a lot of electrical current, this brand is a reliable choice for long-term durability.
- Replacement / Value Brands: These are more budget-friendly options. While they will get the job done, their internal components may not be as robust as a premium brand. They can be a good choice for a truck that sees limited use, but for a daily driver or for maximum peace of mind, a premium brand is often worth the small extra cost.
A Note on Overheating and Headlight Upgrades
If you have upgraded to higher-wattage halogen or LED headlights, the original wiring and switch may not be able to handle the increased electrical draw, causing the switch to overheat. If you have upgraded headlights or your new switch feels hot, consider installing a headlight relay harness. This harness pulls power directly from the battery to the headlights, using the headlight switch only as a low-amperage trigger for the relays. This takes the load off your new switch, prevents overheating, and can even make your headlights brighter.
Headlight Switch Replacement Cost
Replacing the headlight switch is an affordable repair. The main cost is the part itself, with labor being minimal if you do it yourself or have a shop handle it.
| Item | Estimated Cost |
|---|---|
| New Aftermarket Headlight Switch | $27.74 - $54.85 |
| Shop Labor | $60 - $120 |
| Total Estimated Cost | $88 - $175 |
Cost estimates are based on a combination of provided data and typical market rates. Actual costs may vary.
Frequently Asked Questions (FAQ)
Can I replace the headlight switch myself?
Yes, this is a very feasible DIY job for most owners. The process involves disconnecting the battery, reaching under the dash to press a spring-loaded button on the switch body to release the knob and shaft, unscrewing a retaining nut on the dash, and unplugging the electrical connector. Access can be tight, but only basic hand tools are needed.
Are there any recalls for the 1967 GMC headlight switch?
No. A search of the National Highway Traffic Safety Administration (NHTSA) database shows no recalls for the headlight switch on 1967 GMC trucks. Any recalls found for GMC trucks are for much newer models and unrelated issues.
Why do my new aftermarket headlights make the switch hot?
Modern headlights, especially high-wattage halogen bulbs, can draw more power than the original system was designed for. The factory wiring routes all power through the dashboard switch, and this extra load creates heat. To solve this and protect your new switch, install a headlight relay kit.
What's the difference between the 1967 and 1968 headlight switch?
The 1967 switch has 8 electrical pins, while the 1968-72 switch has 7 pins. They are physically interchangeable, but the 8-pin switch has a unique function where it turns the front parking lights off when the headlights are on. Using a 7-pin switch in a '67 will cause the parking lights to stay on with the headlights.
Technical Specifications
OEM Part Numbers: 1995122 1995123 1995142 1995147 1995149 1995150 1995151 1995163 1995164
Connector: 8-Pin Rectangular Plug; Actuation: Pull/Twist Knob; Includes Internal Circuit Breaker and Instrument Light Rheostat.
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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.