Trailer Turn Signal and Brake Lights Dont Work But Running Lights Do
Question:
I have checked all fuses and made sure to follow the wiring diagram from one to the other soldered all wires to ensure best connection but not getting turn signals or trailer brake lights, I do have running lamps.
asked by: Logan
Helpful Expert Reply:
Even if you have checked all of the connection points and fuses, there could still be a short in your wiring somewhere along the line. If you put proper protection on your soldering, the best protection would be using Heat-Shrinkable Tubing # DW05449 with Electrical Tape wrapped around the places that you soldered, then your splices should be okay. Otherwise the connections could jar loose, or in cold conditions they could become brittle and ineffective.
If your connections look good, then what you will want to do next is test the connection on your vehicle end to make sure that you have signal strength getting to your trailer. This will tell us if the problem is on the vehicle or on the trailer. You will also want to make sure the ground connection on the trailer doesn't have rust or corrosion, which can cause a faulty ground. If you are using the 7-Pole to 4-Pole Adapter # 37385 that you referenced, I have a few different options to help you test it.
Since you will be testing not only the wiring harnesses for your tow vehicle, but possibly the wiring on your trailer as well, I recommend using the Draw-Tite Circuit Tester Kit # PTW2993 to do this with. This kit is great for testing harnesses because it features a light and a beeping sound when it receives a signal. This can make testing easier if you don't have an extra set of hands to help you.
If you test the 7-way harness on your vehicle side and it is functioning properly, we can move on to testing the trailer wiring. The Tester Kit has a hook that is included that allows you to pierce a tiny hole into your wiring to see if certain locations are getting power. You can simply move along your trailer wiring until you find where the signal stops. If you need some additional wiring, we off Deka 10 Guage Wire # 10-1-1 that will work for you.
I have attached some demonstration videos for you as well.
Products Referenced in This Question
Primary Wire Heat-Shrinkable Tubing - 14-10 Gauge - Black - 3/16" Diameter - 6" - Qty 25
- Electrical Tools
- Wire Protection
- Heat Shrink Tubing
- 3/16 Inch Diameter
- 6 Inch Long
- Black
- Deka
more information >
Deka Heat Shrink Butt Connector - 16-14 Gauge - Nylon Insulation - Blue - Qty 5
- Wiring
- Wire Connectors
- Butt Connectors
- 16-14 Gauge
- Deka
more information >
Product Page this Question was Asked From
Adapter 7-Pole to 4-Pole and 5-Pole
- Trailer Wiring
- Wiring Adapters
- Multi-Function Adapter
- 7 Round - Blade
- Plug Only
- 4 Flat
- 5 Flat
- Hopkins
more information >
Continue Researching
- Shop: LED Trailer Tail Light with Reflector - Stop, Turn, Tail - Red Lens - Passenger Side
- Shop: LED Trailer Tail Light with Reflector - Stop, Turn, Tail - Submersible - Red Lens
- Shop: LED Trailer Tail Light w/ Reflector - Stop, Tail, Turn - Submersible - 7 Diodes - Round - Red Lens
- Search Results: gas stop
- Search Results: trailer lights
- Shop: Trailer Hitch
- Shop: Right Angle 3-Wire Pigtail for Optronics Trailer Lights - 3-Prong PL-3 Plug - 10" Lead
- Shop: Trailer Wiring
- Shop: Thinline LED Trailer Tail Light - Stop, Tail, Turn - Submersible - 15 Diodes - Red Lens
- Shop: Optronics LED Trailer Tail Light - Stop, Turn, Tail - Submersible - 10 Diodes - Round - Red Lens
- Shop: Brake Controller
- Shop: Gooseneck Hitch
- Shop: Optronics LED Trailer Tail Light - Stop, Tail, Turn - Submersible - 10 Diodes - Round - Red Lens
- Shop: Suspension Enhancement
- Shop: Fifth Wheel Hitch
- Q&A: Does the Tekonsha P3 Trailer Brake Controller Turn Off or Stay On All the Time
- Q&A: Recommended Hitch for a 2024 Mazda CX-90
- Q&A: Lug Nut Torque Chart for Trailer Wheels
- Article: Trailer Wiring Diagrams
- Q&A: Replacement 4-Pin Plug For Truck Camper
- Article: How to Measure for Trailer Hitch Drop
- Q&A: Possible Light Replacement For Monarch 5129 On 1977 Great Divide Trailer
- Q&A: Draw-Tite DT78MR vs 76104 That Fits 2021 Jeep Wrangler
- Q&A: Recommended Trailer Connector And Wiring Harness For 2014 Jeep Wrangler Unlimited With Tow Package
- Article: Wiring Trailer Lights with a 7-Way Plug (It's Easier Than You Think)
- Article: Ball Mount Basics: Weight Capacity, Class, and Size
- Article: 7 Common Questions Everyone Has About Trailer Tires
- Article: Best Camper Jacks
- Article: How to Raise Your Travel Trailer Height