The 2006 Scion xB uses a single H4 headlight bulb per side, also catalogued as 9003 or HB2 in many parts listings. This dual-beam design provides both low and high beams from the same bulb.
Bulb size and designation (H4/9003/HB2)
In North American documentation and aftermarket catalogs, the xB’s headlamps are listed as H4, with the same bulb often referred to as 9003 or HB2. The H4 bulb is a three-filament design that combines low and high beams in one glass envelope, a common setup for many older Toyota-based headlight systems. Using an H4/9003 replacement ensures a proper fit and beam pattern inside the xB’s rectangular headlight housing.
Replacement considerations
When replacing, buy a reputable H4/9003 bulb to ensure reliability and proper performance. If you’re considering brighter options, such as high-performance halogens, LEDs, or HID upgrades, verify compatibility with the headlight housing, wiring, and any local regulations regarding beam color and intensity.
Note: LED or HID upgrades may require additional components (drivers, ballasts, or adapters) and can affect beam pattern and road legality depending on your location and vehicle configuration.
Step-by-step replacement
If you’re replacing the bulb yourself, follow these steps to minimize risk and ensure a proper install.
- Park on a level surface, turn off the engine, engage the parking brake, and open the hood.
- Locate the rear of the headlight assembly and remove the dust cap to access the bulb.
- Disconnect the electrical connector from the bulb socket, then twist or release the bulb retention mechanism to free the bulb.
- Gently remove the old H4/9003 bulb, taking care not to touch the glass with bare fingers.
- Insert the new H4/9003 bulb into the socket, reconnect the wiring, and reattach the retention mechanism and dust cap.
- Test both low and high beams to confirm proper operation and alignment before closing the hood.
Following these steps will help ensure a proper fit, good beam pattern, and safe nighttime visibility after replacing the bulb.
Summary
The 2006 Scion xB uses an H4 (9003/HB2) dual-beam headlight bulb per side. When replacing, choose a quality H4/9003 bulb, handle carefully, and check beam alignment after installation. Upgrading to LEDs or HIDs should be approached with awareness of compatibility and local regulations.