2024 GMC Sierra 1500 Bulb Sizes: Headlight, Tail, Fog & More

As an ASE-certified master technician, I’ve seen firsthand how modern trucks have evolved when it comes to lighting. The 2024 GMC Sierra 1500 is a perfect example of this technological shift. GMC has moved aggressively toward integrated LED lighting across most of its trims, meaning many traditional incandescent bulbs have been replaced with sealed LED assemblies. However, depending on your trim level (Pro vs. SLT, AT4, or Denali), you may still find replaceable bulbs in the rear and interior of the truck.

Whether you are looking to upgrade base model halogens or just need to know what you’re working with before a repair, this guide breaks down the bulb sizes for the 2024 GMC Sierra 1500.

Quick Reference Bulb Size Chart

Note: The 2024 Sierra 1500 relies heavily on integrated LED assemblies for forward lighting across almost all trims. If your truck has LED assemblies, the bulbs cannot be individually replaced; the entire housing must be serviced.

LED vs Halogen Upgrade Considerations

If you have a base model "Pro" trim or an SLE that still utilizes incandescent bulbs for the tail lights, reverse lights, or interior, upgrading to LEDs is a popular modification. However, modern GM trucks are highly sensitive to electrical changes.

• CANBUS Systems: The 2024 Sierra utilizes a strict CANBUS system. If you install aftermarket LEDs in your brake or turn signals, the lower power draw will likely trigger a "bulb out" dashboard warning or cause hyper-flashing.
• Load Resistors: To prevent hyper-flashing in the rear turn signals (if converting from a 7440 halogen to LED), you will need to install inline load resistors or purchase premium CANBUS-ready LED bulbs with built-in resistance.
• Sealed Assemblies: Do not attempt to crack open sealed OEM LED headlight or fog light assemblies to upgrade the diodes. If your factory LED headlights are underperforming or damaged, the entire housing must be replaced.

How to Replace Each Bulb

While the headlights are sealed units, you can still service the rear and interior lights on trims equipped with traditional bulbs.

• Headlights, DRLs, and Fog Lights: Because these are sealed LED units on the 2024 model, replacement requires removing the front grille and unbolting the entire headlight assembly. This is best left to professionals or done under warranty.
• Tail, Brake, and Rear Turn Signals: For trucks with incandescent tail lights, lower the tailgate and remove the two Torx screws securing the tail light housing. Pull the housing straight back to detach it from the retaining pins. Twist the bulb socket counterclockwise to access the 7443 or 7440 bulb.
• Reverse Lights: Accessed the same way as the tail lights. Pull out the old 921 bulb and push the new one straight in. If upgrading to LED, test the polarity before reinstalling the housing (if it doesn't light up, flip the bulb 180 degrees).
• License Plate Lights: Reach behind the rear bumper, twist the socket counterclockwise, and pull it out. Swap the 194 bulb.
• Dome/Map Lights: Use a plastic trim tool to gently pry the plastic lens covers off the overhead console. Pull the 194 bulbs straight out.

Common Lighting Issues for this Generation

The most common issue with the current generation GMC Sierra 1500 isn't burnt-out bulbs, but rather moisture intrusion. Condensation can sometimes build up inside the sealed LED headlight assemblies. While a slight mist that burns off after driving is considered normal by GM, heavy water pooling inside the lens is a defect that warrants a warranty replacement.

Additionally, drivers occasionally report erratic DRL operation, which is usually traced back to a software glitch in the Body Control Module (BCM) rather than a hardware failure. A quick re-flash at the dealership usually resolves this.

If you are dealing with a damaged LED assembly, complex electrical gremlins, or you simply don't want to hassle with dropping your tailgate to change a brake light, don't risk damaging your truck's expensive components. Find a trusted shop on Repairius.