GMC B6000 Headlight Switch Guide: 1983-1991 Models
If your dash lights are out but your headlights still work, your headlight switch is likely the problem.
- The most common symptom of failure is the loss of dashboard lights, even if the headlights still work.
- A burning plastic smell is a critical warning. Always inspect the wiring connector for melting when replacing the switch.
- Replacement is an easy DIY job for most owners, typically taking less than an hour.
- Standard Ignition is a trusted aftermarket brand for this part, while 'Replacement' is a budget-friendly alternative.
Is Your B6000's Headlight Switch Failing?
The headlight switch on this generation of GMC medium-duty truck is a known weak point. The internal components, especially the rheostat that controls dash light brightness, can get hot and fail with age. This can cause a variety of frustrating and dangerous lighting issues. Recognizing the signs early can keep you from getting stuck in the dark.
Common Failure Symptoms
- No Dash Lights: This is the most common sign of failure. The instrument panel lights stop working, even though the headlights may still function perfectly. Rotating the dimmer knob has no effect.
- Flickering or Intermittent Headlights: Your headlights may flash on and off without warning while you're driving. They might work one day and not the next.
- Headlights Won't Turn On: You pull the switch knob, and nothing happens, or only the parking lights come on.
- Burning Plastic Smell: A sharp electrical burning smell from the dashboard is a critical warning sign. This indicates the switch is overheating and could be melting its electrical connector.
Safety Warning: Check for a Melted Connector
If you smell burning plastic or the switch has failed, you must inspect the wiring harness connector that plugs into it. These switches can get hot enough to melt the plastic connector and damage the wires. If the connector is melted, brittle, or shows scorch marks, it must be replaced along with the switch. A new pigtail connector will be needed for this repair.
Choosing the Right Aftermarket Headlight Switch
Since new Original Equipment (OEM) switches for a vehicle of this age are typically discontinued, you will be choosing from aftermarket brands. For the B6000, two common tiers are available.
Brand Tiers
- Standard Replacement (Standard Ignition): Brands like Standard Motor Products (SMP) are well-regarded in the industry for producing parts that meet or exceed original specifications. They often use quality materials, like copper alloy conductors, for reliability and longevity. For a work truck like the B6000, choosing a trusted brand like this is a solid investment for long-term reliability.
- Value/Economy (Replacement): "Replacement" branded parts are a budget-friendly option designed to provide a functional, direct-fit part at a low cost. While they meet the basic requirements to get your lights working again, their long-term durability may not match that of more established brands. This is a viable choice if the initial price is your main concern.
Pro Tip: Installation
Replacing this switch is a straightforward job that most owners can do. The process involves removing the dash trim panel, reaching behind the switch to press a small spring-loaded button to release the pull-knob and rod, unscrewing a retaining nut from the front, and unplugging the electrical connector. The entire process usually takes less than an hour with basic hand tools like a screwdriver.
Headlight Switch Replacement Cost
| Part Type | Price Range |
|---|---|
| New Aftermarket | $27.74 - $54.85 |
| New OEM | Not Generally Available |
| Shop Labor | $75 - $150 |
Frequently Asked Questions (FAQ)
My dash lights don't work, but my headlights do. Is it the switch?
Yes, this is the classic symptom of a failing headlight switch in these trucks. The internal part that controls the dash lights (rheostat) often burns out before the main headlight contacts, making this a very common issue. Replacing the switch assembly is the correct fix.
Is it difficult to replace the B6000 headlight switch myself?
No, it is considered an easy DIY repair. It requires removing the dash bezel to gain access, pressing a release button on the switch body, unscrewing a retaining nut, and swapping the electrical connector. No special tools are needed.
Why do my new headlights flicker?
If you have confirmed the bulbs and wiring are good, flickering is a common sign of a failing headlight switch. The internal contacts wear out and can no longer provide a steady electrical current, causing the lights to flash on and off.
Are there any recalls for the GMC B6000 headlight switch?
No, searches of the NHTSA database did not find any safety recalls or technical service bulletins (TSBs) specifically for the headlight switch on the 1983-1991 GMC B6000.
Technical Specifications
OEM Part Numbers: DS155
Pull-knob style switch with integrated rheostat for dash light dimming.
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.
- GMC B6000: