Wiring Harness Module Worked For A Few Years Then Stopped Working
Updated 10/22/2025 | Published 04/07/2025
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Question:
I installed the T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector on my Mazda CX-9 a few years ago. This week I plugged in the hardness to my trailer and nothing worked. I use the plug in tester and there is no lights that come on. I replaced the battery connector and the 10 amp fuses, still no lights. I dont know if its the whole ground wire that needs replaced due to the exposer to the elements or should I replace the whole thing. Any suggestions. Thanks Pete
asked by: Pete F
Expert Reply:
Hello Pete, thanks for reaching out. I do suggest you check your ground just to make sure, but it does sound to me like your module has gone bad and needs to be replaced. You can test the module by using a wire tester to test the input and output wires on the module. If the input signal is all good, but there is no output signal, you can be sure the converter module is bad. While the modules going bad is rare, it is not entirely unheard of. To replace it, use the Cut # 56016.
I hope this helps. Feel free to reach out with any other questions or comments and I am happy to get back to you.
Product Page this Question was Asked From
T-One 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
- Tekonsha
more information >
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Jesse M.
10/22/2025
Hey Pete, how did things turn out with the wiring harness on your CX-9 after checking the ground and testing the module? Your update could make it easier for the next person troubleshooting a similar issue.