Install a taillight replacement bulb by gaining access to the light bulb, removing the wiring harness, disconnecting the light bulb and placing a new bulb in the socket. The exact process varies by vehicle manufacturer, model and year.
Gaining access to the taillight bulb may require removing an inner cover, commonly located in the trunk, to access the wiring harness on many cars or using screws to remove the tail lamp assembly on most modern trucks and SUVs. Wiring harnesses typically twist and pull free of the assembly, giving vehicle owners access to the bulb and socket. Light bulbs may slip directly out of the socket, require unscrewing or need owners to press in and then turn, similar to a safety cap on a medicine bottle, to free them.
Inserting the new bulb to complete the installation process requires reversing the steps taken to remove the old one. Place the bulb in the socket and screw, twist or turn until it fits securely. Place the wiring harness back in the assembly, and turn it until it locks into place. Align the taillight assembly with the screw holes on the car, and place the screws back into their slots. Tighten the screws.