Low beam: H11; high beam: 9005; fog lights (if equipped): H11.
Bulb sizes by function
These sizes reflect the common factory-halogen configuration for the 2018 Tahoe LS. Regional specs, trims, or aftermarket headlights can differ, so always double-check before purchasing replacements.
- Low beam: H11
- High beam: 9005 (HB3)
- Fog lights (if your Tahoe LS is equipped with them): H11
Knowing the exact bulb sizes helps ensure proper fit and lighting performance. If your vehicle has aftermarket headlights or a different regional spec, sizes may vary.
How to verify the exact bulb size on your Tahoe
To be certain before buying replacements, use these verification steps.
- Consult the owner's manual or the headlight section for the specified bulb type.
- Open the hood and inspect the bulb or socket; many bulbs have the size stamped on the base.
- Check the GM parts catalog or contact a dealership with your VIN for an exact match.
- Match the current bulb to a catalog image or part number if you’re replacing one-to-one.
Always handle bulbs with gloves to avoid oil contamination on the glass, and ensure the electrical connector is fully seated after replacement.
If you’re replacing bulbs yourself
Here are the general steps for replacing standard halogen headlight bulbs in a Tahoe. Note that steps can vary by headlight design (projector vs. reflector) and trim, so consult the manual if unsure.
- Park safely, turn off the engine, and open the hood.
- Remove the dust cap from the back of the headlight housing to access the bulb.
- Disconnect the wiring connector, then release the bulb’s retaining mechanism and remove the bulb.
- Install the new bulb, reconnect the wiring, and reseal the dust cap.
- Test the headlights before finishing the job and replace the cover if needed.
If your Tahoe has aftermarket headlights or a nonstandard configuration, the replacement process or bulb type may differ. When in doubt, seek professional assistance.
Summary
For a 2018 Tahoe LS with standard halogen headlights, the typical configuration uses H11 for low beams and 9005 for high beams, with H11 also used for fog lights if the vehicle is equipped with them. Always verify against your manual, current bulbs, or dealer resources, as specifications can vary by region, trim, or aftermarket upgrades.