Troubleshooting Non-Working Lights On A Roadmaster Nighthawk Tow Bar

Updated 10/22/2024 | Published 10/21/2024

Products Featured in This Question

Replacement 7-Way to 6-Way Coiled-to-Straight Cord for Roadmaster Nighthawk Tow Bar - 8' Long

(20)

$128.92

Digital Multimeter with 42" Long Test Leads - LED Display

(2)

$21.68

Question:

I installed the replacement cord for my Nighthawk today. When I first plugged it in to the RV, the LED lights on the tow bar flickered, but when I connected it to the car, nothing worked - not the turn signals and not the Invisibrake or brake lights, and not the LED lights. I checked that the plugs were fully ed, and I checked to ensure the wiring of the car-side plug was correct. Would an issue with the LED wiring connection cause the entire cord to fail or would that just cause an issue with the LED lights? If the problem isnt related to the LED wiring, what else should I check? Is there a fuse in the RV and/or the car that should check? Thank you.

asked by: Debbie S

Expert Reply:

Hi Debbie,

The lights are being powered by the motorhome's 7-way so if the lights aren't going out there's got to be some sort of issue with the motorhome's 7-way. When they flickered did they just shut off after or were they still working? The lights should be getting power from your trailer running light fuse so I would definitely check if that's blown. You could also just have a loose/corroded ground connection or damage to your 7-way wiring on the motorhome so I would trace through that, checking for power with a multimeter # PT89ZR to ensure the light signal is running all the way from that fuse box to the 7-way.

Let me know what you find and we can keep troubleshooting.

expert reply by: Kevin C

Debbie S.

10/22/2024

Thank you, Kevin. I will check the motorhome's 7-way. Even so, since everything was working fine prior to my replacing the power cord*, I suspect that the issue has something to do with my install of the replacement power cord. My concern is less with the LED lights and more with the function of the car turn signal lights, Invisibrake, etc. If there were an issue with my wiring of the LED lights, would that cause the entire power cord to fail? Also, could an LED wiring issue have caused a fuse to blow somewhere upstream or downstream? Thank you. *Even though my previous power cord was working, I replaced it due to some wear I was seeing.

Kevin C.

10/22/2024

@DebbieS If you cut into the spliced into the wrong wires or didn't fully seal them up with some electrical tape over your connector there's also the chance that some bare wire is shorting to the metal inside the tow bar housing. The trailer running light/lamp fuse is where this gets power so it would be the fuse to check. Your turn signals and brake signals are on separate wires so if they aren't working then either multiple fuses are blown or you have an issue with the wiring in the 7-way or with how the # RM-1676-7R was wired in. I always check for problems by starting at the power source and working my way back to the lights to find where power stops and what the issue is.

Debbie S.

10/22/2024

@KevinC Thank you. I checked the 7-way with a multimeter, and all was good there. Then, I re-did all the wiring on the tow bar - LED and plug. All good now! Will check it again a few days before my next departure. Thanks again!