How to Change a Headlight on a 2004 Chevrolet TrailBlazer

by Justin Cupler

    The “Trailblazer” name actually made its debut in the 1999 model year, but as a premium trim level for the existing Blazer. In 2002, Chevrolet chose to do away with the Blazer altogether and replace it with the Trailblazer. Your 2004 Chevrolet Trailblazer's headlights are well hidden by various components under the hood, and replacement may seem like a job for a professional. In fact, you can replace a headlight fairly quickly by removing the grille and pulling the headlight assembly.

    Items you will need

    • Flat-head screwdriver
    • No. 9005 light (high-beam only)
    • No. 9006 light (low beam only)

    Removal

    Step 1

    Open your Trailblazer’s hood and pry across the top of the grille with a flat-head screwdriver to unfasten the four clips securing the grille to the front of the vehicle. Carefully pull the top of the grille outward to allow you to get your hand behind it, then pry the three retaining clips – two on the bottom and one in the middle – from the front of the SUV. Pull outward on the left and right edges of the grille’s center bar – the bar with the Chevrolet emblem – to unfasten the two clips that secure it to the headlight assembly. Remove the grille from the vehicle.

    Step 2

    Find the metal locking tabs on the top, outer edges of the headlight assembly with the burned-out headlight bulb and pry the tabs upward with a flat-head screwdriver to release them. Pull the headlight assembly outward to remove it from the front of your Trailblazer. Do not pull the headlight assembly out too far or you may damage the wires for the lights.

    Step 3

    Unplug the three wiring harnesses from the headlight assembly – one on the lower, inside corner, one upper outside corner and one on the bottom. Remove the headlight assembly from the vehicle. Pull the plastic cover from the rear of the burned-out headlight bulb to expose it.

    Step 4

    Unplug the wiring harness from the burned-out headlight bulb. Twist the bulb counterclockwise to unlock it and pull the bulb from the headlight assembly.

    Step 5

    Repeat steps 2 through 4 to replace the headlight bulb in the other headlight assembly, if needed.

    Installation

    Step 1

    Guide a new headlight bulb – bulb No. 9005 for the high-beam or bulb No. 9006 for the low beam – into its hole in the headlight assembly and rotate the bulb clockwise to lock it into place. Do not touch the glass part of the bulb with your bare hands, as the oils from your hands can cause premature bulb failure. Plug the wiring harness into the bulb’s receptacle and press the circular cover back into place over the rear of the bulb.

    Step 2

    Plug the harnesses into their respective receptacles on the rear of the headlight assembly and slide the headlight assembly back into its bed on the front of the SUV. Hold rearward pressure on the assembly and press the locking tabs downward to lock the headlight assembly into place.

    Step 3

    Align the tabs on the rear of the grille with their slots in the front of your Trailblazer. Press the outer edges of the center bar to engage the outer clips, then press around the center portion of the grille to engage the remaining clips.

    Tip

    • With the extra work you need to perform to access the headlights, it may be in your best interest to replace all of the headlights at once to avoid the older headlights burning out just a short time later.
    • To replace the entire headlight assembly, simply twist the remaining bulbs from the old headlight assembly, transfer them into the new assembly and twist them into place.

    References