Chevrolet P20 Headlight Switch Guide: 1975-1989
Having trouble with your step van's lights? Here's what you need to know about replacing your headlight switch.
- Headlights cutting out intermittently is a critical symptom pointing to a failing switch.
- For long-term reliability, choose a known aftermarket brand like Standard Ignition over a generic 'Replacement' part.
- If you replace the switch and it fails again quickly, you likely have an underlying wiring problem that needs to be fixed.
- Replacing the switch is a simple DIY task that requires basic tools and about 30 minutes.
Is Your P20 Headlight Switch Failing?
The headlight switch on an older commercial vehicle like the Chevrolet P20 handles a lot of electrical current. Over decades of use, the internal contacts can wear out, corrode, or fail from heat. This can lead to confusing and dangerous lighting problems. Because these vans share a lot of parts with other GM trucks of the era, the issues are well-known. Often, the switch itself is the point of failure, but sometimes it's a symptom of a larger electrical problem.
Common Symptoms of a Bad Headlight Switch
If you're experiencing any of the following, your headlight switch is a likely culprit:
- Intermittent Headlights: Your headlights cut out while driving and then come back on by themselves after a few moments. This is often the internal thermal breaker in the switch tripping due to a short or overload, then resetting as it cools.
- Flickering or Inoperative Dash Lights: You lose illumination on your instrument panel, or the dimmer function no longer works when you rotate the knob.
- Switch is Hot to the Touch: A switch that feels warm or hot after use is a sign of high resistance, either in the switch itself or in the wiring connected to it. This can lead to a melted connector or a fire hazard.
- Lights Won't Switch Modes: The switch fails to properly move between off, parking lights, and headlights, or one mode doesn't work at all.
- Total Failure: None of the lights controlled by the switch turn on, indicating a complete internal failure.
Check for Other Problems First
Repeatedly burning out new headlight switches is a strong indicator of another issue in the electrical system. Before replacing the switch, inspect the wiring connector for signs of melting or corrosion. Also, check for bad grounds or frayed wires in the headlight circuit. Upgrading your headlights to high-wattage bulbs without adding relays can also overload and destroy the factory switch.
Choosing the Right Aftermarket Headlight Switch
For the 1975-1989 P20, original OEM headlight switches are no longer produced. Your choice is between different tiers of aftermarket parts.
Brand Tiers
- Premium Aftermarket (e.g., Standard Ignition): Brands like Standard Motor Products (SMP) are well-known in the repair industry and have a reputation for quality. They often use materials similar to the original parts, such as copper alloy conductors, and are designed to meet or exceed OE specifications. Choosing a reputable brand like this is your best bet for long-term reliability and proper fit.
- Economy (e.g., Replacement): "Replacement" is often a private-label or generic brand sold by online retailers. While the price is attractive, the quality can be inconsistent. These parts may work fine, but they might not last as long or fit as perfectly as a part from a more established manufacturer. For a critical safety component like a headlight switch, the extra cost for a name-brand part is often worth the peace of mind.
Pro Tip: Install Headlight Relays
To make your new switch last longer and potentially make your headlights brighter, consider installing a headlight relay harness. This is a common modification on older vehicles. The relays take the high-current load of the headlights off the switch. The switch then only needs to handle a tiny amount of current to activate the relays. This drastically reduces heat and wear on the switch.
Cost of a New Aftermarket Headlight Switch (1975-1989 Chevrolet P20)
| Part Type | Price Range |
|---|---|
| New Aftermarket Headlight Switch | $31.80 - $58.42 |
Frequently Asked Questions (FAQ)
Is it difficult to replace the P20 headlight switch?
No, it is generally an easy job for a DIYer. The main steps involve disconnecting the battery, removing the dash bezel, and then releasing the switch from the dashboard. The knob and shaft are removed by pressing a small, spring-loaded button on the body of the switch itself while pulling the knob out. Then you can unscrew the retaining nut, unplug the electrical connector, and install the new switch.
Do I need any special tools?
Typically, you will only need basic hand tools like a screwdriver set and possibly a socket set. No highly specialized tools are usually required for this job.
Are there any recalls or TSBs for this part?
Searches of the National Highway Traffic Safety Administration (NHTSA) database and other technical resources show no specific recalls or technical service bulletins (TSBs) for the headlight switch on the 1975-1989 Chevrolet P20. Any issues are addressed through standard diagnostic and repair procedures.
My headlights and high beams don't work. Is it the main switch?
It could be, but you should also check the dimmer switch. On these older GM vehicles, the dimmer switch (usually on the floor) selects between high and low beams. Power runs from the main headlight switch to the dimmer switch. If the dimmer switch fails, it can prevent both high and low beams from working, even if the main switch is good.
Technical Specifications
OEM Part Numbers: 1995122 1995123 1995142 1995147 1995149 1995150 1995151 1995163 1995164 1995165 1995173
Dash-mounted, pull/push and rotating knob operation. Controls headlights, parking lights, instrument panel dimming, and dome light. Typically features a built-in thermal circuit breaker.
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.
- 🛍️ Shop This Part
- Is Your P20 Headlight Switch Failing?
- Common Symptoms of a Bad Headlight Switch
- Check for Other Problems First
- Choosing the Right Aftermarket Headlight Switch
- Brand Tiers
- Pro Tip: Install Headlight Relays
- Cost of a New Aftermarket Headlight Switch (1975-1989 Chevrolet P20)
- Frequently Asked Questions (FAQ)
- 🎟️ Get 5% Off