Troubleshooting Trailer Connector on 2003 Dodge Ram 3500
Question:
I have a 2003 dodge 3500 some one wired a trailer plug for a 7way everything works fine but when you apply brakes you lose turn signals I have tried everything but no luck
asked by: Larry R
Expert Reply:
When you say that everything works fine, are you referring to the lights on the truck, or the lights on a trailer when its plugged in?
If the problem is with the lights on the trailer, unplug the trailer and use a circuit tester like part # PTW2993 on the trailer connector as each lighting function is activated. This will help determine if the wiring problem is on the truck or in the wiring on the trailer.
If you find the problem is on the vehicle wiring, the easiest course of action would be to abandon the existing 7-way and install a new one. The quickest, easiest way to do this would be to simply install a 4-pole connector tapped directly into the taillight circuits. Part # 118381 would do this very easily. Then install the # 37195 adapter by plugging it into the 4-pole. The blue wire on the # 37185 would connect to the brake output voltage circuit that connected to the # 2 terminal on the existing 7-way. The black wire from the 37185 adapters would connect to the wire connected to the # 4 terminal on the existing 7-way. The purple wire would connect to the wire feeding the center pin and the white wire would ground to the truck frame.
If you're testing on the truck 7-way checks out okay, then the problem lies within the trailer wiring. Check connector on the trailer, and make sure it's not damaged or corroded. Check that the ground is securely made to clean, non-corroded metal. Also, trace the right and left turn/brake circuits, usually a yellow and a green wire, from the connector back to the lamps, looking for loose connections. Make sure each lamp is securely grounded to the trailer frame.
I have linked you to some troubleshooting and wiring FAQ articles that you might find helpful.
Products Referenced in This Question
T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector
- Custom Fit Vehicle Wiring
- Trailer Hitch Wiring
- No Converter
- Custom Fit
- 4 Flat
- Tekonsha
more information >
Adapter 4-Pole to 7-Pole and 4-Pole
- Trailer Wiring
- Wiring Adapters
- Multi-Function Adapter
- 4 Flat
- Plug and Lead
- 4 Flat
- 7 Round - Blade
- Hopkins
more information >
Product Page this Question was Asked From
Hopkins Endurance 5th Wheel/Gooseneck 90-Degree Wiring Harness with 7-Pole Plug
- Custom Fit Vehicle Wiring
- Fifth Wheel and Gooseneck Wiring
- 10 Feet Long
- Custom Fit
- 7 Round - Blade
- Hopkins
more information >
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Thomas H.
6/27/2020
You need a tail light converter my 2003 2500 dodge refuses to allow right turn and brake to to tied together as well as left side