Replacing the headlights on a 2016 Scion iM is a straightforward DIY project that takes about 45 minutes with basic hand tools. Whether you're dealing with clouded lenses that reduce night vision or a burnt-out bulb, swapping out your headlights restores essential road visibility and keeps your vehicle safe for nighttime driving.
The 2016 Scion iM uses halogen projector headlights for its low and high beams, while later models and certain trims incorporated distinct daytime running light styling. Over time, plastic housings degrade under UV exposure, and halogen filaments burn out. Knowing how to access the headlight assembly, select the correct bulb sizes, and properly align the beams ensures you get factory-level performance without paying shop labor rates.
Tools and Parts Required for the Job
Before you pop the hood, gather the right equipment to prevent stripped fasteners or damaged clips.
- Replacement Bulbs or Assembly: Verify your specific part needs. The low beam typically uses an H11 halogen bulb, while the high beam uses a 9005 (HB3) bulb. If you are replacing cracked or severely oxidized entire housings, order a certified aftermarket or OEM replacement assembly.
- Socket Set & Ratchet: A standard metric socket set (10mm is most common for bumper and fender fasteners).
- Screwdrivers: Phillips #2 and flathead screwdrivers for plastic push-pins and cover screws.
- Trim Removal Tool: Essential for popping plastic clips without snapping them.
- Clean Microfiber Towels and Nitrile Gloves: Never touch halogen bulb glass with bare fingers. The oils from your skin create hot spots on the quartz glass, causing premature bulb failure.
Step-by-Step 2016 Scion iM Headlight Bulb Replacement
If your lenses are clear and you only need to change a dead bulb, you don't need to remove the entire headlight housing. You can access the bulbs directly from under the hood.
- Prep the Vehicle: Turn off the ignition, engage the parking brake, and pop the hood. Allow the engine bay to cool completely if the car was recently driven, as halogen bulbs reach extremely high temperatures.
- Access the Back of the Headlight: Look behind the headlight assembly. You'll find rubber dust caps or tight working spaces, particularly on the driver's side where the battery sits. You may need to unclip the windshield washer fluid filler neck or move the battery cover slightly to gain hand clearance.
- Disconnect the Power Harness: Firmly press the release tab on the plastic electrical connector attached to the rear of the bulb, then pull straight back to unplug it. Don't yank on the wires.
- Remove the Old Bulb: Twist the bulb counterclockwise about a quarter-turn until it unlocks from the reflector housing, then pull it straight out.
- Install the New Bulb: Wearing nitrile gloves, insert the new bulb into the housing alignment slots without touching the glass. Twist it clockwise until it locks securely into place.
- Reconnect and Test: Push the electrical harness back onto the bulb base until it clicks. Turn on your headlights to verify the new bulb works before buttoning everything back up.
Complete Headlight Assembly Removal and Replacement
If your headlight housing is cracked, heavily fogged inside, or damaged from a minor front-end scrape, replacing just the bulb won't fix your visibility issues. Swapping the full assembly requires removing part of the front bumper cover to access hidden mounting bolts.
- Disconnect the Battery: Disconnect the negative battery terminal to prevent any accidental electrical shorts while unplugging the front harness.
- Remove Upper Grille and Bumper Fasteners: Pop the plastic clips along the top radiator support cover using a trim tool. Remove any lower bumper screws securing the plastic bumper fascia to the inner fender liners.
- Release the Bumper Corners: Gently pull outward on the corners of the front bumper near the wheel wells to unclip it from the fender retainers. You don't need to remove the entire bumper; dropping the top corners and letting it sag slightly is usually enough to expose the hidden lower headlight mounting bolt.
- Unbolt the Headlight Assembly: Locate the three primary mounting bolts securing the headlight housing—typically two on top and one tucked near the bottom corner. Remove them using your 10mm socket.
- Disconnect Wiring and Extract: Pull the housing forward slightly to access the main multi-pin wiring harness connector. Unplug it completely, then maneuver the old headlight assembly out of the fender bay.
- Install the New Assembly: Position the new headlight housing in place, plug the wiring harness back in, and secure it with the mounting bolts. Torque them snugly, but don't over-tighten into the plastic mounting tabs. Reattach the bumper fascia and clips.
Headlight Beam Alignment and Adjustment
After replacing a full assembly, checking your beam alignment is mandatory. Misaligned headlights either blind oncoming traffic or leave you driving "blind" past 50 feet.
Find a flat parking lot facing a blank wall at night, parking about 25 feet away. Measure the height from the ground to the center of your headlight lenses. Mark that same height on the wall with tape.
Using a long Phillips screwdriver inserted into the adjustment gears on the back of the headlight housing, turn the vertical adjustment screw until the top cutoff of the beam sits slightly below your wall mark (roughly 2 inches lower at 25 feet). For official safety specifications, consult resources like the NHTSA Vehicle Safety Guidelines.
Frequently Asked Questions
Can I upgrade my 2016 Scion iM to LED bulbs?
Yes, aftermarket LED replacement bulbs are available in H11 and 9005 sizes. However, ensure you purchase bulbs with a beam pattern designed to mimic standard halogen filament placement. Cheap LEDs in projector housings can scatter light awkwardly and create blinding glare for other drivers.
Why do my Scion iM headlights keep getting foggy?
Factory polycarbonate headlight lenses feature a protective UV coating that degrades over time from sun exposure and road salt. Once this layer wears away, the plastic oxidizes and turns yellow. You can restore temporary clarity with a restoration kit, but heavy internal moisture means the housing seal has failed and needs replacement.
Do I need to disconnect the battery to change a headlight bulb?
It's not strictly mandatory for a simple bulb swap, but it is best practice to prevent accidental shorts, blown fuses, or triggering dashboard warning lights while handling live electrical connections.
How do I know if my headlight fuse is blown?
If both low beams or both high beams fail simultaneously, check your interior and under-hood fuse boxes before buying new bulbs. A single blown fuse rarely knocks out just one side, but a shared relay or fuse failure will disable both. You can reference specific wiring layouts via Toyota Owner Manuals since Scion vehicles share mechanical lineage with Toyota.
