Troubleshooting Running Lights Not Working After Curt 4-Way Installation
Updated 01/05/2026 | Published 09/22/2024
Question:
Hello Jameson, before I submit a comment I wonder if you could help me out. The E-trailer hitch is fantastic and I highly recommend it! However, the wiring harness does not work completely. The tail lights do not turn on. It does work for the blinkers and brake lights, but not for the riding lights, which are very important. Also, when the lights are turned off, there remains some type of low-level current still passing through, which keeps the trailer lights partially on dimly at all times. This causes a battery drain, so I need to disconnect the harness when not driving the vehicle. Can you solve this riddle for me. I am very handy and can use a volt-meter if needed. Thanks, Tom.
asked by: Tom
Expert Reply:
Hello Tom; I'm not Jameson but I can still help you with troubleshooting your # C56217 installation. There isn't much to this wiring harness so hopefully it is an easy fix. The first thing I would do is double check the ground. Make sure that screw is all the way down and secure on your bare-metal surface. If it is a little loose it can cause this kind of problem.
The other thing I would check is the connections. Go ahead and disconnect the wiring harness and then plug it back in, making sure it is fully seated. If neither of these solve the problem you can test for power.
I'm sure you don't have power at the connector, but you can start there. Assuming there is no power, jump back to the connector on the 4-way at the plug and test on either side. Do the same thing with the wiring that has the converter. If you have power running into the converter but not out then it sounds like a bad converter that needs to be replaced with another # C56217.
The lights staying on sounds like you have LEDs on the trailer. This isn't uncommon since residual power can keep them lit like that for a while. Assuming they are LED lights check back after an hour or two and they probably won't be lit. Even if they are, the power draw is so low it won't kill your battery. If you have incandescent lights, or the lights never shut off and you're hooked up for a really long time, I would continue to do what you have been and just disconnect the 4-way when not in use.
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 >
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Robin H.
1/5/2026
Hey Tom, how did things turn out after checking the ground and connections on your Curt wiring harness? Were you able to get the tail lights working correctly? Your update could make it easier for others troubleshooting the same issue.