BK LED on Curt 7-Way Adapter, Part # C57674, Remains Lit Even Without a Trailer Connected

Expert Reply:

If you do not have a proportional brake controller (but instead have a time-delay type) the LED being lit could indicate a short to the controller output circuit. In some cases the manual brake switch on your controller may be partly engaged; this would also cause a signal to be sent to the 7-way BK LED. You can correct this by flipping the manual switch on and off several times to clean the contacts.

If you are using a proportional type brake controller such as the Prodigy P2, part # 90885, there will always be a very small voltage from the controller sent to the 7-way connector. This is because the controller is always checking to see if a trailer is connected.

The current draw from an LED is quite small (a tiny fraction of an amp) so this does not pose any concerns for battery drain. Your Curt 7-way is supposed to function in this manner.