Installing Trailer Wiring Harness on a 1994 Toyota Pickup Installing Trailer Wiring Harness on a 1994 Toyota Pickup How do I install my trailer lights wiring harness to my 94 Toyota Pickup? asked by: Dakota. Expert Reply: You can use part # 118379 and it will plug in to the tail light connectors behind the tail lights. If you have a T100 model, you will need to use some other parts. Toyota Pickup Tail Light Assembly, 1995, 1994, 1993, 1992 wwwarts›Toyota›PickupThe Toyota pickup tail light assembly is composed of several lights, each with an important role to fulfill. If one of the lights is busted or if the lens is cracked or damaged, you have to repair it right away.