Dorman 888-5900 Headlight Bulb Cap

Headlight Bulb Cap for Halogen Assemblies

Dorman 888-5900 is a replacement headlight bulb cap for halogen headlamp assemblies. It restores the seal at the rear of the headlight housing to help keep dust and moisture out when the original cap is missing, cracked, or damaged.

Built from gray plastic with a twist-on mounting method, this cap matches the fit and function of the original part for select applications. It is a practical OE-style solution for drivers searching for a headlight bulb cap for Dodge Ram 2500, Dodge Ram 3500, or Ram 2500 and Ram 3500 headlamp service.

• Replacement headlight bulb cap for halogen headlamp assemblies
• Gray plastic construction for a factory-style appearance
• Twist-on design for secure installation at the rear of the headlight housing
• Helps seal out dust and moisture to protect the headlamp interior
• Matches the fit and function of the original cap when the OE part is damaged or missing
• Dorman 888-5900 for select OE-style headlight repair applications

Detailed Product Information

This headlight bulb cap is made to restore the integrity of the headlight assembly by closing off the bulb opening after service or repair. The cap uses a plastic body with a 3.5-inch outside diameter and a 2.25-inch depth, and it installs by twisting into place rather than using bolt holes or threaded fasteners. The included gaskets help support a tighter seal at the housing interface. For shoppers comparing Dorman 888-5900 against OE references, this part cross-references 2509599C92 for the same application.

What It Helps Fix

• Missing or broken headlight bulb cap
• Dust intrusion inside the headlamp housing
• Moisture entering the rear of the headlight assembly
• Loss of sealing after bulb replacement or headlamp service
• Damaged factory cap that no longer locks in place correctly

Installation Notes and Tips

Confirm the headlamp uses a halogen bulb cap with a twist-on mounting style before ordering. Inspect the housing opening and sealing surface for debris, cracks, or distortion before installation. Clean the mating area so the cap and gaskets seat evenly, then twist the cap into position until it is fully secured. This part is not a universal fit item and should be matched to the specific headlight assembly design.

Quality Assurance

Dorman replacement parts are built to match original fit and function for the listed application. Dorman 888-5900 is a direct replacement-style headlight bulb cap intended to restore sealing performance in the headlamp assembly.