Troubleshooting Non-Functioning Running Lights on Trailer
Question:
2005 chevy pickup not running lights on trailer all the rest of the lights work
asked by: Kelley S
Expert Reply:
When all lights on a trailer work except for the running lights this often has to do with a grounding issue. If a ground wire on the vehicle or trailer is loose or attached at a rusty or painted surface it may be able to pass enough current for some lights but not others. Turn and brake lights do not remain on continuously like running lights do. This is why that lighting function, with it's higher current demand, tends to be where a weak ground connection shows up.
This issue has an easy fix.
Check the white ground wire on both the vehicle wiring harness and the trailer connector. Make sure both are tightly affixed to a clean bare metal spot. You can try sanding/cleaning the existing grounding points or create a new grounding point if you prefer. Be sure all paint, primer, rust, grease, dirt and salt are cleaned away before you make the new ground connection.
I suggest you protect that connection by applying dielectric grease like # 11755. You can apply this to the ring terminal before securing it and also after, where the grease will act as a barrier to incoming contaminants.
You can also directly test the running light circuit on the trailer. Simply unplug the trailer and apply 12V input power to the running light circuit (this is the pin next to the ground). Connecting a 12V battery directly to the trailer lighting circuits will tell you what's happening on the trailer without the vehicle wiring coming into the picture also. If the running lights work in this way then you know the issue is in the vehicle.
Products Referenced in This Question
Dielectric Grease for Electrical Connectors, 2 oz.
- Accessories and Parts
- Trailer Wiring
- Wiring
- Dielectric Grease
- LubriMatic
more information >
Product Page this Question was Asked From
Pollak Replacement 7-Pole, RV-Style Trailer Connector Socket - Vehicle End
- Trailer Wiring
- Trailer Connectors
- Vehicle End Connector
- Plug Only
- 7 Round - Blade
- Pollak
more information >
Continue Researching
- Q&A: Trailer Running Lights Do Not Work but Brake Lights and Turn Signals Do Work
- Shop: Removable, 8" Poly Caster Assembly for etrailer or Ram Jacks - 1,500 lbs
- Q&A: Troubleshooting No Running Lights on Trailer but Turn Signals and Brake Lights Work
- Shop: 4" Offset Ball for B&W Turnoverball Gooseneck Trailer Hitch for Dodge Ram 1500
- Shop: Hopkins 7-Way RV Style Connector with Molded Cable - Trailer End - 8' Long - RV Standard
- Shop: Cam-Action Lockable Door Latch w/ 36" Pipe for Enclosed Trailers - Zinc Plated Steel
- Shop: 4" Offset Ball for B&W Turnoverball Gooseneck Trailer Hitch for Toyota Tundra
- Q&A: Why Are Trailer Running Lights Coming on When Brakes are Applied
- Q&A: All Trailer Taillight Functions Work Except Running Lights
- Video: B And W Turnoverball Gooseneck Trailer Hitch 4 Inch Offset Ball Review
- Article: Wiring Trailer Lights with a 7-Way Plug (It's Easier Than You Think)
- Article: Troubleshooting 4 and 5-Way Wiring Installations
- Q&A: Magnetek Series 6300A Model 6332 Replacement Converter
- Video: Choosing the Right Trailer Wiring
- Article: Trailer Wiring Diagrams
- Shop: Universal Installation Kit for Trailer Brake Controller - 7-Way RV and 4-Way Flat - 10 Gauge Wires
- Shop: Trailer Hitch
- Search Results: hitch
- Q&A: What is the Difference Between a Class II and a Class III Hitch?
- Search Results: trailer hitch
- Video: Choosing the Right Brake Controller
- Shop: etrailer Hitch Pin Alignment Collar for Hitch Accessories - 2" Hitches
- Shop: Trailer Wiring
- Search Results: trailer brake controller
- Q&A: Lug Nut Torque Chart for Trailer Wheels
- Shop: Brake Controller
- Article: Brake Controller 7- and 4-Way Installation Kit (ETBC7)
- Shop: Suspension Enhancement
- Search Results: brake controller
- Article: How to Choose the Right Trailer Hitch Class