Troubleshooting Electrical Issue With Roadmaster Nighthawk Tow Bar RM-676
Updated 02/04/2026 | Published 01/26/2026
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Question:
Have you folks had electrical issues with the Roadmaster Nighthawk 676 tow bar? Mine has a short or back feed in it somewhere that sends 6 volts DC to both the left and right Turn Signal/Brake lights when the motorhome tail lights are ON. Also, I can see the red LEDs on both sides of the tow bar light dimly when the motorhome tail lights are ON. With the motorhome tail lights OFF, everythinmg works fine.
asked by: Jim J
Expert Reply:
Hi Jim, good question, and you’re on the right track with your thinking. Electrical issues like that aren’t at all common with the Roadmaster Nighthawk # RM-676, but what you’re describing does line up with a backfeed or short, not a failure of the tow bar itself.
When the motorhome’s running lights are on, a small amount of voltage bleeding into the turn/brake circuits usually points to a wiring issue, most often in the coiled umbilical cable or one of the plug ends. I’d start by checking both ends of that cable closely for pinched wires, corrosion, or terminals touching where they shouldn’t. Even a small nick or loose strand can cause the LEDs to glow dimly like you’re seeing.
I’d also verify the tow vehicle wiring (or diode kit if you’re using one) to make sure there isn’t a shared ground or damaged diode allowing voltage to cross circuits. In a lot of cases, simply replacing the coiled cable solves it, and if it comes to that, the replacement is part # RM-1676-7R.
Bottom line, this isn’t a known defect with the Nighthawk, it’s almost definitely a wiring or cable issue. Check that out and let me know what you find out. I am happy to continue to help troubleshoot if needed.
(click to enlarge)
Gordon
1/29/2026
We've had the Roadmaster towbar with LED lights for about 2 1/2 years maybe. We've used it a number of times including a 5000 trip through Alaska. We had one electrical problem, but it seems to be an issue the pins on the electrical cable not firmly mating to the tow vehicles electrical "outlet". The fix is to clean and re-spread the cylindrical split "tines" on the two vehicle side. Probably no help.
Scott J.
1/29/2026
We have the Roadmaster Night Hawk and it has performed great for us!! Happy to hear RM helped you out Jim J. Great Customer Service from etrailer and RM ????
Scott F.
1/29/2026
We’ve been using the Nighthawk for two years and have not had any problems. It’s good to be aware of this potential problem and what is causing it.
Product Page this Question was Asked From
Roadmaster Nighthawk All-Terrain Tow Bar w/ LED Lights - Non-Binding - RV Mount - 8,000 lbs
- Tow Bar
- Hitch Mount
- Telescoping - Non-Binding
- Aluminum
- 8000 lbs
- Fits Roadmaster Base Plates - Direct Connect
- Stores on RV
- Cables Included
- Roadmaster
more information >
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on Tow Bar
Jim J.
1/28/2026
Thanks Jesse. I did find this particular fault and it definitely lies somewhere within one or both of the LED arrays of the tow bar. While unhooked from the towed vehicle, the red LED's on both sides of the towbar would light very dimly when the coach tail lights were ON and I would measure 6 volts DC on both the yellow and green wires (right & left turn/brake signals) of the Roadmaster 6 pin connector. Upon cutting the wires from the main cable to the two LED arrays, the voltage backfeed problem was resolved. No more issues with low voltages going where they shouldn't when the tail lights are ON. Roadmaster is replacing both the main coiled 7 pin to 6 pin cable and both LED arrays at no cost. Thanks to Tim at Roadmaster for taking care of this potentially unsafe issue for me! And thank you for your help and assistance. Jim J.