2020 Chevrolet Suburban Bulb Sizes

Quick reference

The 2020 Chevrolet Suburban offers a range of lighting options, primarily split between traditional halogen setups on lower trims (LS, LT) and advanced LED lighting on higher trims (Premier, High Country, and some sport/off-road packages like RST or Z71). Understanding these differences is crucial when considering bulb replacements or upgrades.

For the low beam, high beam, and fog lights, LS and LT trims typically utilize H11 bulbs for low beams and fog lights, and 9005 bulbs for high beams. These are standard halogen bulbs. Premier and High Country trims, along with certain packages, come equipped with integrated LED headlamps and fog lamps from the factory. In these cases, individual bulbs are not replaceable; the entire assembly typically needs to be replaced if a component fails, though LED components are known for their longevity.

Daytime Running Lights (DRLs) are predominantly integrated LED systems across most trims, offering a modern light signature. However, some halogen headlamp-equipped models may use a W21W bulb for their DRL function.

Front turn signals often use a 7443 halogen bulb. However, some premium trims with LED headlamp assemblies may feature integrated LED front turn signals within the headlamp unit. Rear turn signals and brake lights commonly share a 7443 halogen bulb, while tail lights also use the 7443 bulb, often sharing the filament with the brake light function in a dual-filament bulb. Reverse lights are typically a 921 halogen bulb.

For smaller exterior lights, the license plate lights and front and rear side markers generally use a 194 halogen bulb.

Inside the cabin, the dome and map lights (front, middle, and rear rows) can vary. Some 2020 Suburban models still use 578 halogen festoon bulbs, particularly on lower trims, while most come equipped with integrated LED interior lighting from the factory, providing brighter and more efficient illumination.

LED vs halogen upgrade considerations

Upgrading from halogen to LED bulbs in your 2020 Chevrolet Suburban can significantly improve visibility and modernize the vehicle's appearance. However, there are several considerations:

CANBUS Errors: Modern vehicles like the 2020 Suburban utilize a CANBUS (Controller Area Network Bus) system to monitor electrical components. Halogen bulbs draw more power than LED bulbs, and if you install LED bulbs without proper resistors, the CANBUS system may detect the lower power draw as a "bulb out" error. This can trigger dashboard warning lights (e.g., "Check Headlights"), hyper-flashing turn signals, or even cause the lights not to function at all. To avoid this, you will need LED bulbs with built-in CANBUS decoders or external load resistors.

Adapters Needed: For some LED conversions, especially for headlights, you might need specific mounting adapters to properly seat the new LED bulb into the factory housing. The base designs of many aftermarket LED bulbs mimic halogens, but slight variations can necessitate an adapter for a secure fit and proper beam pattern.

Beam Pattern: Aftermarket LED bulbs, particularly for headlights and fog lights, need to be carefully chosen to ensure they produce a correct and safe beam pattern. Poorly designed LEDs can scatter light excessively, blinding oncoming drivers, or create dark spots that reduce your visibility. Look for LED bulbs designed to mimic the filament placement of their halogen counterparts to maintain the factory beam cut-off.

Heat Dissipation: LED bulbs generate heat, and effective heat dissipation is crucial for their longevity. Most quality LED bulbs come with integrated cooling fans or heatsinks. Ensure there is adequate space around the bulb in the housing for proper airflow.

How to replace each bulb

Headlights (Low/High Beam): Access is usually from the engine bay. Twist the bulb counter-clockwise to remove. Disconnect the wiring harness, then install the new bulb and reconnect. Some trims may require fender liner removal for better access.

Fog Lights: Typically accessed from underneath the front bumper or by removing part of the fender liner. Twist to remove the bulb, disconnect the harness, and replace.

DRL (if applicable): May require removal of the headlight assembly or access from behind the bumper. Consult your owner's manual for specific instructions.

Front Turn Signal: Often accessed by turning the wheel and opening a panel in the fender liner, or directly from within the engine bay.

Rear Turn Signal, Brake, Tail, Reverse Lights: Open the liftgate. There are usually retaining screws or clips holding the tail light assembly in place. Remove these, carefully pull the assembly outwards, twist the desired bulb socket to remove, and replace the bulb.

License Plate Lights: Usually, two small screws hold the clear lens in place above the license plate. Remove the screws, pop off the lens, twist out the bulb socket, and replace.

Side Markers: These are often small lenses that can be pried out gently with a plastic trim tool, revealing the bulb socket behind.

Dome/Map Lights: Gently pry off the clear lens cover using a plastic trim tool to avoid scratching the plastic. Twist or pull the old bulb out (depending on type) and insert the new one.

Common lighting issues for this generation

The 2020 Chevrolet Suburban, being a relatively newer model, generally has reliable lighting systems. However, some common issues, particularly with halogen setups, can include:

Premature Halogen Bulb Failure: Especially for headlights and fog lights, halogen bulbs have a finite lifespan and can burn out. This is a normal wear-and-tear item. Using reputable brands can help improve longevity.

Corroded Sockets: Less common on newer vehicles, but moisture or road salt can occasionally lead to corrosion in bulb sockets, causing intermittent operation or complete failure. Cleaning the contacts or replacing the socket may be necessary.

Flickering (Aftermarket LEDs): If you install aftermarket LED bulbs without proper CANBUS decoders, you might experience flickering, especially after the vehicle starts or when the electrical system fluctuates. This indicates an incompatibility with the vehicle's electrical monitoring system.

DRL Malfunctions (Integrated LEDs): While rare, if an integrated LED DRL circuit fails, it often requires replacement of the entire headlamp assembly, which can be costly.

Taillight Condensation: Over time, seals in taillight assemblies can degrade, allowing moisture to enter and cause condensation. While not directly a bulb issue, it can obscure light output and potentially lead to electrical issues if left unaddressed.

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