How to Connect the Wiring for a Turn Signal on a Trailer
- 1). Set the parking brake on both the vehicle and the trailer. Place wheel chocks behind and in front of at least one wheel on the trailer.
- 2). Crawl under the rear of the vehicle and find the wiring harness. Vehicles that are set up for towing will usually have the wiring harness near the trailer hitch or close to a tail light. The wiring harness will be a collection of different colored wires and will always have one each of green, yellow, white and brown wires.
- 3). Find the wiring harness plug. Nearly all vehicles made since the mid-1990s which are set up for towing have a wiring adapter for a tow vehicle. Plug the wiring harness from the tow vehicle into the wiring harness on the lead vehicle. If the number of wires on each is different, use an additional adapter as a bridge between them. If the lead vehicle does not have a wiring adapter of any sort, continue to the next step.
- 4). Open the vehicle's hood and disconnect the battery. Return to the vehicle's wiring harness and splice the wires to install the T-1 connector. Cut each wire, strip 1/2 inch of insulation from each end of the splice and connect the ends to the same colored wire on the T-1 connector by twisting the wire together. Depending on the style of T-1 connector, the layout will be slightly different, but the colors are standardized on all wiring harnesses. Wrap the spliced connections with electrical tape.
- 5). Plug the trailer's wiring harness into the T-1 adapter. Reconnect the battery and test all of the lights. If any of the lights do not work, disconnect the battery and check the wiring connection.
