2018 Chevrolet Suburban — Bulb Sizes (Headlight, Tail, Fog)

Quick reference

Notes

• The sizes above reflect the most common factory configuration for 2018 Suburban (K2XX platform). Some trims (especially LTZ/Premier) add LED signature DRLs and, in some cases, LED fog lamps that are part of a sealed assembly rather than a replaceable bulb. Always verify by trim and visual inspection of the lamp housing.

LED vs halogen upgrade considerations

• Headlights: If your Suburban uses H11/9005 halogen bulbs, quality LED retrofit bulbs can improve lumen output and color temperature. Choose fanless or compact‑fan LEDs that fit the dust cover depth. Aim for focused beam patterns to avoid glare. Projector low beams accept upgrades better than reflectors.
• Fog lights: LS/LT with 5202 halogen can be upgraded to LED 5202. Premier/LTZ with factory LED fogs are typically sealed; replace the whole lamp if it fails.
• DRL/turn signal CANBUS: Upgrading 7444NA or 7443 to LED can trigger hyper‑flash or bulb‑out warnings. Use CANBUS‑ready LEDs or add 6‑ohm load resistors per circuit. Mount resistors to metal away from wiring—they run hot.
• Interior and license bulbs: 194 and 921 LEDs work well and generally do not need resistors. Pick warm‑white for OEM look, cool‑white for modern appearance.
• Polarity and fit: Wedge bases (194/921/744x) insert either way, but some LED replacements are polarity‑sensitive. Test before reassembling.

How to replace each bulb

• Low beam (H11): Turn the wheel outward, remove the front fender liner access clips, reach the rear of the projector, twist H11 counter‑clockwise, swap, and reinstall without touching the glass.
• High beam/DRL (9005): Access from behind the headlamp via the same wheel‑well panel; twist to remove. If used for DRL, expect more frequent wear—consider long‑life 9005.
• Fog light (5202/LED): From below the bumper, remove the splash shield fasteners. For 5202, twist to release. For LED modules, unplug and remove the lamp housing if replacement is needed.
• Front turn/park (7444NA): Access behind the headlamp, rotate the socket, remove bulb, and seat the new 7444NA firmly. Verify amber color behind clear lenses.
• Front side marker (194): Quarter‑turn the small corner socket in the headlamp, pull the 194, and push in replacement.
• Tail/brake/turn (7443): Open liftgate, remove tail lamp screws, pull the assembly straight back to release pins, rotate the socket, and replace the 7443. Test brake and turn before reinstalling.
• Reverse (921): Same tail lamp removal; swap the white 921 in the clear lens position.
• Rear side marker (194): Remove tail lamp and access the small side socket; replace 194.
• License plate (194): From below the liftgate garnish, pop the lens, twist the socket, and replace 194.
• Interior map (194): Pry the lens of the overhead console carefully with a trim tool, pull 194 and install LED or incandescent.
• 2nd/3rd‑row dome (194): Pry lens at the notch, swap 194.
• Cargo/rear dome (921): At rear headliner lamp, pry lens and replace 921.

Tips

• Disconnect battery when working near airbag zones or if sockets are tight.
• Use dielectric grease on exterior bulb bases to reduce corrosion.
• After LED headlight upgrades, check aim against a wall and adjust to prevent glare.

Common lighting issues for this generation

• Hyper‑flash after LED turn upgrades: Add proper resistors or CANBUS bulbs.
• Moisture in tail lamps: Check housing seals and vent ports; replace gasket if recurring.
• DRL/high beam burnouts: 9005 used as DRL sees high duty cycle—use long‑life bulbs or upgrade to quality LEDs with proper thermal management.
• Flicker with LEDs: The BCM’s pulsed voltage can cause flicker on DRL/turn circuits; choose LED bulbs designed for PWM/CANBUS.
• Fog lamp cracking or haze: Road debris and heat cycles can craze lenses; consider protective film or full housing replacement.

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