2021 Jeep Gladiator Bulb Sizes: Headlight, Tail, Fog & Interior Chart

As an ASE-certified master technician, I’ve worked on countless Jeep Wranglers and Gladiators over the years. The 2021 Jeep Gladiator (JT generation) is a rugged, highly customizable pickup, but its factory lighting can be a point of confusion for many owners. Jeep offered the Gladiator with both standard incandescent/halogen lighting (common on Sport and Willys trims) and a premium factory LED lighting group (standard or optional on Rubicon, Mojave, and Sahara trims).

If you are looking to replace a burnt-out bulb or upgrade your factory halogens to LEDs, this guide covers everything you need to know about the 2021 Jeep Gladiator’s bulb sizes.

Quick Reference: 2021 Jeep Gladiator Bulb Size Chart

The chart below applies primarily to Gladiators equipped with the factory halogen lighting package. Note: If your Gladiator has the factory LED package, most of the exterior lights (headlights, tail lights, fog lights, and front signals) are sealed LED units. If an OEM LED fails, the entire housing must be replaced rather than a single bulb.

*Note on Fog Lights: Depending on your exact bumper setup (plastic vs. steel Rubicon bumper), the halogen fog light bulb is typically a PSX24W, but some factory configurations may use a 2504.

LED vs. Halogen Upgrade Considerations

Upgrading your halogen Gladiator to aftermarket LEDs is one of the most popular modifications, but it requires some electronic know-how. The Gladiator uses a CANBUS (Controller Area Network) electrical system that continuously monitors bulb resistance.

• CANBUS Errors & Flickering: LED bulbs draw significantly less power than halogens. If you install standard LED bulbs, the Gladiator’s computer will think the bulb is burnt out. This results in dashboard warning lights, hyper-flashing turn signals, or pulsing/flickering headlights.
• Anti-Flicker Modules / Resistors: To prevent this, you must buy CANBUS-ready LED bulbs with built-in resistors, or install inline PWM (Pulse Width Modulation) anti-flicker harnesses.
• Flash Programming: Many Jeep owners use an OBD2 programmer (like the Tazer JL Mini or JScan app) to tell the truck's computer that LEDs have been installed. This changes the computer's voltage expectations and completely eliminates the need for bulky inline resistors.

How to Replace Each Bulb

Replacing bulbs on the JT Gladiator ranges from incredibly simple to slightly tedious. Here is a quick technician’s breakdown:

• Headlights (H13): You cannot access the headlight bulbs from under the hood. You must remove the front grille. Fortunately, the grille is held on by six pop-clips along the top and a few tension clips at the base. Once the grille is off, remove the three 10mm bolts holding the headlight housing, pull the housing out, and swap the bulb.
• Fog Lights (PSX24W): These are best accessed from underneath the front bumper. You may need to remove the plastic air dam or peel back the front wheel well liner slightly to get your hand in there. It’s a simple twist-and-pull mechanism.
• Front Turn Signals / DRL (7443): These are housed in the front fenders. Access them by removing the bolts/clips holding the front edge of the inner fender liner and reaching up into the fender.
• Tail Lights, Brake, and Reverse (3157/7440): Open the tailgate. Look at the inside lip of the bed where the tail light is mounted; you will see two bolts (often 8mm or T30 Torx). Remove them, slide the tail light housing straight back, and you will have full access to the bulb sockets on the back.
• Interior Dome/Map Lights (194): Use a non-marring plastic trim tool to gently pop off the overhead console lenses.

Common Lighting Issues for This Generation

1. Hyperflashing After Upgrades: As mentioned, putting an LED in a halogen socket will cause rapid blinking. Fixing it requires load resistors or an OBD2 flash.
2. Moisture in Factory LED Housings: Some 2020-2021 Gladiators with the premium OEM LED package experience condensation inside the sealed housings. While a little fogging is normal in high humidity, standing water is a defect. If you have water pooling inside an OEM LED headlight, it often needs a full replacement (which may be covered under your factory warranty).
3. Loose Headlight Harnesses: If you've been off-roading or tackling washboard trails, the main harness connector on the back of the headlight can occasionally work itself loose, leading to intermittent low beam failures.

Whether you're sticking to reliable halogens or upgrading your rig for night-time trail rides, always double-check your bulb sockets before purchasing replacements.

Need help installing a new set of headlights, wiring in load resistors, or diagnosing a CANBUS error? Find a trusted shop on Repairius.