2004 hummer h2 headlight bulb sizepdf
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2004 Hummer H2 Headlight Bulb Size Guide [PDF Quick Reference & Playbook]
2004 Hummer H2 Headlight Bulb Size: The Complete Replacement Playbook
Facing a blown headlight on your 2004 Hummer H2 doesn't have to mean hours at the auto parts store or deciphering dense technical manuals. This playbook gives you every bulb size, socket type, and replacement step you need — organized so you can get back on the road fast.
Key Takeaways
- Low beam bulbs: 9005 (HB3) — the most common failure point on the 2004 H2
- High beam bulbs: 9007 (HB4)
- Fog lights: 9006 (HB4) — note the difference from high beams despite similar base
- Turn signals (front): 3157A (amber) or 7506
- Tail / brake / reverse bulbs: 1157 (dual-filament) and 1156 (single-filament)
- Side markers: 921 (WY21W) — wedge-base, 21-watt
- Always verify before buying — aftermarket housings and trim-level differences can affect fitment
- Nitrile gloves are mandatory — skin oils on halogen glass cause premature filament failure
2004 Hummer H2 Bulb Size Reference Chart
The table below covers every exterior lighting position on a stock 2004 Hummer H2. Use it as a quick lookup when ordering replacements or checking your existing bulbs.
| Lighting Position | Bulb Size | Base Type | Wattage | Notes |
|---|---|---|---|---|
| Low Beam (Driver Side) | 9005 / HB3 | P20d | 65W | Most frequently replaced bulb |
| Low Beam (Passenger Side) | 9005 / HB3 | P20d | 65W | Identical to driver side |
| High Beam (Driver Side) | 9007 / HB4 | P20d | 65W | |
| High Beam (Passenger Side) | 9007 / HB4 | P20d | 65W | |
| Fog Light (Each) | 9006 / HB4 | P22d | 55W | NOT interchangeable with 9007 |
| Front Turn Signal | 3157A / 7506 | P21W wedge | 21W | Amber lens recommended |
| Front Side Marker | 921 / WY21W | Wedge | 21W | Clear or amber option available |
| Rear Turn Signal / Brake | 1157 / 7443 | Bayonet (double contact) | 21W / 5W | Dual-filament; brake + turn |
| Rear Tail Light | 1156 / 7443NA | Bayonet (single contact) | 5W | Running light only (often combined with 1157) |
| Reverse Light | 1156 / 921 | Bayonet / Wedge | 16W / 21W | Verify both positions; varies by assembly |
| Cargo Area Light | SV8.5 / Festoon 8.5mm | Festoon | 5W | Oval festoon style |
Step-by-Step Headlight Bulb Replacement Playbook
Follow this sequential workflow to replace low-beam and high-beam bulbs on your 2004 Hummer H2 without damaging the housing, wiring harness, or new bulb.
Tools & Supplies Checklist
- New 9005 (low beam) and/or 9007 (high beam) bulbs — buy a pair, not just one
- Nitrile or latex gloves
- Phillips-head screwdriver (if removing grille for access)
- Flashlight or work light
- Clean lint-free cloth or paper towels
- Socket wrench set (optional, for wheel-well liner removal)
Preparation Phase
- Park the H2 on a flat, level surface and engage the parking brake
- Turn the ignition off and remove the key
- Wait at least 10 minutes for the headlight assemblies to cool if recently running
- Open the hood and secure the prop rod
- Locate the targeted headlight assembly (driver or passenger side)
- Remove the weatherproof dust cover by twisting it counterclockwise (~¼ turn)
Bulb Removal Procedure
- Disconnect the electrical connector from the back of the bulb by pressing the retention tab and pulling straight back
- Release the bulb retaining clip or spring clip (squeeze and pivot outward on most H2 assemblies)
- Grasp the bulb base only — never the glass — and pull straight out
- Inspect the O-ring or rubber seal on the dust cover; replace if cracked or brittle
- Check the wiring harness connector for corrosion or melted plastic (common on higher-mileage H2s)
Bulb Installation Procedure
- Do not touch the glass of the new bulb with bare fingers
- If you accidentally touch the glass, clean it thoroughly with isopropyl alcohol and a lint-free cloth before installation
- Insert the new bulb into the socket and rotate until the tabs align with the housing slots
- Reattach the retaining clip and confirm it locks securely
- Plug the electrical connector back in until it clicks