2018 Toyota Highlander Bulb Sizes

Quick Reference

The 2018 Toyota Highlander, a popular choice for families, offers a mix of lighting technologies. Most models come equipped with halogen bulbs for primary lighting functions such as low and high beams, fog lights, and turn signals. However, some taillight functions are integrated LED units, particularly for the main tail light portion, which means individual bulbs are not replaceable for this function. It's important to note that the Daytime Running Lights (DRL) on many Highlander trims share the high beam bulb, operating at a lower wattage.

Trim-Level Variations

While most Highlanders will utilize the bulb sizes listed above, it's worth noting that some higher trims or specific packages might have variations, though less common for the 2018 models in terms of major headlight changes like HID or projector systems. Always verify with your owner's manual or by visually inspecting the existing bulb if you are unsure.

LED vs Halogen Upgrade Considerations

Upgrading your 2018 Toyota Highlander's halogen bulbs to LED can significantly improve visibility and give your vehicle a more modern look. However, there are a few important considerations:

• CANBUS Errors: Modern vehicles like the 2018 Highlander use a CANBUS (Controller Area Network Bus) system to monitor electrical components. LED bulbs draw less power than their halogen counterparts, which can sometimes trigger "bulb out" warnings on your dashboard. To resolve this, you may need to use LED bulbs with built-in CANBUS decoders or install external load resistors. Without them, your vehicle's computer might think a bulb is burnt out.
• Adapters Needed: For some applications, particularly headlights, the base of the LED bulb or its cooling fan might be larger than the original halogen bulb. This could require special adapters or modifications to the dust caps to ensure a proper fit and seal.
• Beam Pattern: Not all LED bulbs are created equal. Poorly designed LED headlight bulbs can scatter light excessively, leading to glare for oncoming drivers and a less effective beam pattern. Look for LED bulbs that are designed to mimic the filament placement of the original halogen bulb for optimal performance.
• DRL Functionality: If your DRLs use the high beam bulb, replacing them with standard LED high beams might affect the DRL function. Some LED bulbs are designed to work as both high beams and DRLs, but it's something to consider.

How to Replace Each Bulb

Replacing bulbs on your 2018 Toyota Highlander is generally straightforward, but some locations require more access than others.

• Low Beam & High Beam Headlights: Access is usually gained from under the hood. You'll likely need to twist the bulb counter-clockwise to remove it from the housing. Be careful not to touch the glass of new halogen bulbs, as oils from your skin can create hot spots and shorten their lifespan.
• Fog Lights: These are typically accessed from underneath the front bumper or by removing part of the fender liner. You may need to turn the steering wheel to gain better access.
• DRL (shared with High Beam): Follow the same procedure as replacing your high beam bulbs.
• Front Turn Signals: Accessible from under the hood, often by twisting out the socket.
• Rear Turn Signals, Brake Lights, Reverse Lights: You'll typically need to open the tailgate and remove a few screws holding the taillight assembly in place. Once the assembly is loose, you can access the bulb sockets from the back.
• License Plate Lights: Usually involves removing a couple of screws near the license plate light housing on the tailgate.
• Front Side Marker: Accessible from the fender well, often requiring a simple twist to remove the socket.
• Dome Light: Pry off the clear plastic lens cover carefully with a plastic trim tool or small screwdriver.
• Map Lights: Similar to the dome light, carefully pry off the lens covers.

Always ensure your vehicle's lights are off and the ignition is turned off before attempting any bulb replacement. Consult your owner's manual for specific instructions and diagrams.

Common Lighting Issues for this Generation

Owners of the 2018 Toyota Highlander, and this generation in general, may encounter a few common lighting issues:

• Halogen Bulb Burnout: Like all halogen bulbs, they have a finite lifespan. Low beam and high beam bulbs, being used frequently, are often the first to go. Keep a spare set on hand.
• Dimming Headlights: Over time, the clear plastic headlight lenses can become cloudy or oxidized due to UV exposure, reducing light output. Headlight restoration kits can often resolve this, but severe cases may require lens replacement.
• Intermittent Electrical Issues: Though less common, sometimes a loose connection or a faulty relay can cause lights to flicker or fail intermittently. If replacing the bulb doesn't fix the issue, it's best to have an automotive electrician diagnose the problem.
• License Plate Light Corrosion: Due to exposure to road salt and moisture, the sockets for license plate lights can sometimes corrode, leading to intermittent or complete failure. Cleaning the contacts or replacing the socket can resolve this.

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