2019 GMC Acadia Bulb Sizes (Headlight, Tail, Fog)

Quick reference

The 2019 GMC Acadia, a popular mid-size SUV, offers a variety of lighting configurations depending on the trim level and optional packages. Understanding the correct bulb sizes is crucial whether you're replacing a burnt-out bulb or considering an upgrade to LED lighting.

For many Acadia owners, especially those with SLE and SLT trims, the primary headlights will utilize halogen bulbs. The low beam typically uses an H11 bulb, while the high beam uses an H9. These are common halogen bulb types, readily available and relatively inexpensive. However, if you have a higher trim level such as the Denali or an Acadia equipped with the optional HID (High-Intensity Discharge) projector headlamps, your low beam will be a D3S HID bulb. It's important to note that even with HID low beams, the high beam often remains a separate H9 halogen bulb.

Fog lights, if equipped, generally take an H16 bulb. Daytime Running Lights (DRLs) can vary; many 2019 Acadias use a 7443 incandescent bulb, but some higher trims or specific packages may feature integrated LED DRL strips. Front turn signals are typically 7443NA (amber) bulbs, and rear turn signals use a 7440A (amber). The brake and tail lights often share a dual-filament 7443 red incandescent bulb, where one filament powers the tail light and the second, brighter filament activates for braking. Reverse lights commonly use a 7440 bulb.

Inside the cabin, the dome light frequently uses a 578 festoon-style bulb, while map lights and other auxiliary interior lights will often use smaller 194 bulbs. License plate lights and side marker lights (both front and rear) also typically use 194 incandescent bulbs.

LED vs halogen upgrade considerations

Upgrading from halogen to LED bulbs in your 2019 GMC Acadia can offer several benefits, including brighter light, a whiter color temperature, and longer lifespan. However, there are important considerations to keep in mind:

• CANBUS Errors: Modern vehicles like the Acadia use a CANBUS (Controller Area Network Bus) system to monitor electrical components. LED bulbs draw less power than halogen bulbs, which can sometimes trigger "bulb out" warnings or flickering on your dashboard. To avoid this, you may need LED bulbs with built-in CANBUS decoders or external load resistors.
• Adapters Needed: For headlights, some LED kits may require specific adapter rings or mounting collars to properly seat the LED bulb in the headlight housing, especially if you're replacing an H11 or H9 halogen. Always check the fitment specific to your vehicle.
• Beam Pattern: Not all LED bulbs are created equal. Poorly designed LED bulbs can create a scattered beam pattern in a housing designed for halogen bulbs, leading to glare for oncoming drivers and less effective light distribution for you. Look for LED bulbs that mimic the filament placement of the original halogen bulb for optimal performance.
• Dimmimg: For interior lights, ensure that any replacement LED bulbs are compatible with your vehicle's dimming system to prevent issues like flickering or residual glow when the lights are off.

How to replace each bulb

• Headlights (Low/High Beam): Access is usually from under the hood. You may need to remove a plastic cover or shield. Twist the bulb counter-clockwise to remove, disconnect the electrical connector, and then connect the new bulb and twist it back into place.
• Fog Lights: Often accessed from underneath the front bumper or by removing fender well liners. There may be a small retaining screw or tab to release the housing.
• DRL, Front/Rear Turn Signals, Brake/Tail/Reverse Lights: These are typically accessed from the rear of the light assembly. For exterior lights, you might need to open the tailgate or access them from inside the trunk/cargo area by removing trim panels. Twist the bulb socket counter-clockwise to remove.
• License Plate Lights: Usually involves removing a couple of small screws to take off the clear lens cover, then twisting out the bulb socket.
• Side Marker Lights: Similar to license plate lights, often requiring removal of a small lens or housing to access the bulb.
• Dome/Map Lights: Gently pry off the lens cover using a plastic trim removal tool to avoid scratching. The bulbs are usually pushed or pulled out from their sockets.

Always consult your owner's manual for specific instructions and warnings regarding bulb replacement.

Common lighting issues for this generation

The 2019 GMC Acadia, like many vehicles, can experience some common lighting-related issues:

• Premature Bulb Burnout: While less common with LED systems, halogen bulbs can burn out prematurely due to vibrations or voltage fluctuations. If one bulb burns out repeatedly, it might indicate a wiring or voltage regulator issue.
• Flickering Lights: This can be a sign of a loose connection, a failing bulb (especially with halogens nearing the end of their life), or an incompatibility issue if aftermarket LEDs are installed without proper CANBUS decoders.
• DRL Malfunctions: Issues with Daytime Running Lights can sometimes be traced to faulty DRL modules or wiring problems. If one DRL is out, it's often the bulb, but if both are out or behaving erratically, a deeper electrical issue might be present.
• Condensation in Headlight/Taillight Assemblies: While not a bulb issue directly, condensation inside the light housing can lead to premature bulb failure or impede light output. This typically indicates a failing seal in the assembly.

Find a trusted shop on Repairius.