Why Does the Curt 6-Way Round LED Circuit Tester Flip the 12V Power and Electric Brake Pins
Updated 01/05/2026 | Published 09/15/2024
Question:
the 12V indicator does NOT illuminate when plugged into the trailer connector. However the indicator labeled EB does. That is not consistent with my 7 blade tester used on another trailer connector. I was under the impression that the 12V light was suppose to illuminate if properly wired.
asked by: Paul E
Expert Reply:
Hey Paul!
Yes, if you have 12V power present at the back of your vehicle, then the 12V light on the Curt 6-Way Round LED Circuit Tester # C76NR should be illuminated. Right now the "EB" light is for the electrical brake.
With all of that being said, it's not uncommon to see what you're seeing on your 6-Way connector. As frustrating as it is, some horse trailers will swap the 12V and electric brake pins which I'm pretty sure is what you're seeing. If you have an electric brake controller you can verify this by activating the manual override to see if the 12V light illuminates when you do that.
As long as the pins on your 6-Way match the functions of the 6-Way on your trailer then you'll be fine, but you may have to rewire something in order for them to match.
Attached is an article we've written on 6-Way wiring you can reference as well.
Product Page this Question was Asked From
Curt 6-Way Round LED Circuit Tester - Vehicle End
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Jerred H.
1/5/2026
Hey Paul, did you get a chance to test the 6-way connector using the manual override on your brake controller to see if the 12V light came on? Knowing how that turned out could help others sorting through the same wiring issue.