2024 Chevrolet Silverado 3500HD — Bulb Sizes (Headlight, Tail, Fog)

Quick reference

Notes: The 2024 Silverado 3500HD lineup (WT, LT, LTZ, High Country) commonly uses halogen, socketed bulbs on WT/LT trucks and sealed LED lighting on LTZ/High Country. Always verify by VIN or a visual check before ordering.

LED vs halogen upgrade considerations

• CANBUS/load monitoring: The truck monitors several exterior circuits. When replacing incandescent 7443/7444 and 194 bulbs with LEDs, use CANBUS-ready LEDs or add appropriate resistors to prevent hyperflash (turn signals) or bulb-out warnings.
• Headlights: WT/LT halogen housings (H11 low, 9005 high) can accept LED retrofit bulbs, but beam pattern and glare depend on the LED design. Choose quality, focus-correct LED retrofits; avoid high-wattage units that can melt housings. LTZ/High Country LED headlamps are sealed; upgrading means replacing the entire assembly.
• DRL interaction: On halogen trucks the DRL uses the high-beam 9005 at reduced voltage (PWM). Some LED 9005 retrofits flicker in DRL mode unless they’re PWM-compatible.
• Fog lamps: H11 fogs on WT/LT are an easy LED upgrade; use models with compact drivers and proper cutoff to avoid glare.
• Interior: 194 and 578 replacements rarely need resistors, but choose non-polarity LEDs for easier installs.

How to replace each bulb

• Low/high beam (WT/LT halogen): Turn wheel inward, remove fender liner fasteners for access, or reach from engine bay depending on side. Twist the dust cap, rotate the H11 (low) or 9005 (high) counterclockwise to release. Avoid touching halogen glass. Refit the cap to keep moisture out.
• LED headlamps (LTZ/High Country): Service is by headlamp assembly replacement only; no individual bulbs.
• Fog light (WT/LT): From beneath the bumper, unplug connector, rotate H11 counterclockwise. Check O‑ring condition and aim after reinstall.
• DRL: Same physical bulb as the 9005 high beam on halogen trucks—replacement procedure is identical.
• Front turn signal: Access behind headlamp on WT/LT; twist the 7444NA socket out, swap bulb. Test hazards to confirm operation. LED headlamps use sealed LED—no bulb service.
• Tail/stop/turn (WT/LT): Lower the tailgate, remove the two tail lamp screws, pull the lamp rearward. Twist the 7443 socket out, replace, and reseat the foam seal to keep dust out. LTZ/HC tails are LED; the whole lamp must be replaced if inoperative.
• Reverse: With the tail lamp removed, twist the 921 socket out, swap bulb, and test in reverse (set parking brake, use a spotter).
• License plate: From beneath/behind the bumper garnish, pop the lens, replace 194, and snap back in.
• Side markers: Front uses the headlamp side marker socket (194) on halogen assemblies; replace as for front turn signal access. Rear side marker is part of the tail/park function—no separate bulb on most trims.
• Interior map: Pry the lens on the overhead console carefully with a trim tool, swap the 194, mind polarity for LEDs.
• Dome: Pry the rear overhead lens, replace the 578 festoon (or 194 if so equipped). Don’t bend the contacts.

Common lighting issues for this generation

• Hyperflash after LED swaps: Occurs if 7443/7444 turn bulbs are changed to LED without resistors or CANBUS LEDs. Fix with 6–8Ω, 50W resistors or a proper CANBUS LED.
• Moisture in tail lamps: Check foam seals and mounting studs; reseal or replace if condensation persists.
• Headlamp performance (halogen): Many owners seek upgrades due to dim halogens. Use high-quality bulbs (H11/9005) or projector-friendly LEDs; verify aim per SAE specs after any change.
• DRL flicker with LED 9005: Choose PWM-compatible LEDs or add a decoder/anti-flicker harness.
• Inoperative LED elements (LTZ/HC): Because LEDs are sealed, failures typically require full lamp replacement; check warranty/TSBs.

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