Troubleshooting Running Lights on Trailer Not Working With Curt # C56217 on 2018 Toyota Highlander
Updated 06/11/2021 | Published 06/09/2021
Products Featured in This Question
Question:
Installed and turn and brake lights work but regular headlights on , tail lights don’t light
asked by: Chris T
Expert Reply:
First you will need to determine if the lighting issue is in the vehicle side of the wiring or the trailer. A Test Light # PTW2992 will help you to test the 4-way plug. Simply connect the clamp side of the test light to either the ground lug of the 4-way for to a good chassis ground. You can then activate the headlights on your 2018 Toyota Highlander to check for power to the brown wire connector. This is the one closest to the ground terminal on the 4-way.
If you have power here the problem is in the trailer wiring. You can continue to use the test light to follow the wiring to the lights looking for a break in the wiring or where it may have shorted to ground. I have linked an article below that will cover the trailer wiring.
If you do not have power at the 4-way you will want to inspect the connectors on the wiring harness to determine if there may be a damaged pin or a wire has come out of the connector. I have linked a video below for reference as well.
Lastly check to ensure that the fuse for the wiring is still good and that there are no damaged fuses in the vehicle circuit for the running lights.
Product Page this Question was Asked From
Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector
- Custom Fit Vehicle Wiring
- Trailer Hitch Wiring
- Vehicle End Connector
- Powered Converter
- No Tow Package
- 4 Flat
- Plug and Lead
- Plug-In
- Hidden
- CURT
more information >
Featured Help Information
Instructions
Miscellaneous Media
Continue Researching
- Shop: Trailer Wiring
- Q&A: Troubleshooting Low Voltage at Running Lights Pin with Curt Harness on Toyota Highlander
- Q&A: Troubleshooting Installation of Tow Ready Wiring Harness on 2016 Toyota Highlander
- Shop: Curt Powered Tail Light Converter with 4-Pole Flat Trailer Connector
- Shop: DeeMaxx Hydraulic Brake Line - Rubber - 3/16" Brass Male Inverted Flares - 20' Long
- Shop: DeeMaxx Hydraulic Brake Line - Rubber - 3/16" Brass Male Inverted Flares - 1' Long
- Shop: DeeMaxx Hydraulic Brake Line - Rubber - 3/16" Brass Male Inverted Flares - 18' 4" Long
- Q&A: Trouble Preventing Brass Brake Line Fittings From Leaking On a Trailer
- Article: Brake Controller 7- and 4-Way Installation Kit (ETBC7)
- Shop: Trailer Hitch
- Video: The Low-Down on the Curt Powered Tail Light Converter with 4-Pole Flat Trailer Connector
- Q&A: What is the Difference Between a Class II and a Class III Hitch?
- Search Results: trailer hitch
- Search Results: trailer wiring
- Video: Fifth Wheel Towing Made Simple with Daniel
- Article: Trailer Wiring Diagrams
- Shop: Universal Installation Kit for Trailer Brake Controller - 7-Way RV and 4-Way Flat - 10 Gauge Wires
- Q&A: What is the Difference Between a 4-Way and 7-Way Trailer Connector
- Video: Clean Up Your Trailer Wiring
- Search Results: trailer tires and wheels
- Shop: etrailer Trailer Hitch Receiver - Custom Fit - Matte Black Finish - Class III - 2"
- Article: How to Measure for Trailer Hitch Drop
- Q&A: Lug Nut Torque Chart for Trailer Wheels
- Shop: Suspension Enhancement
- Video: Curt Powered Tail Light Converter Installation - 2023 Kia Telluride
- Article: Wiring Trailer Lights with a 7-Way Plug (It's Easier Than You Think)
- Shop: Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector
- Search Results: trailer hitch ball mount
- Q&A: Installation Time for Blue Ox BX1128 Flat Tow Base Plate Kit for 2016 Jeep Grand Cherokee
- Shop: Brake Controller
on Custom Fit Vehicle Wiring
