Adjusting the Brightness of the Curt Spectrum Trailer Brake Controller Without Trailer Connected

Updated 10/30/2025 | Published 02/23/2025

Question:

I have a Curt Spectrum hooked up to my 2024 Chevy 1500 Trail Boss. I haven’t towed with it yet, but I am getting blue LEDs on the edges with every press of the brake pedal so I know it’s hooked up correctly. My question is, are you supposed to be able to adjust the brightness and things without a trailer hooked up? I can’t get it to do anything when I hit the button or turn the knob. But I do get the blue LEDs with every press of the brake pedal.

asked by: Woodrow T

Expert Reply:

Hey Woodrow, thanks for reaching out!

You should be able to adjust the Curt Spectrum Trailer Brake Controller # C51170 brightness without a trailer connected by rotating the control knob right and left. Just make sure it has the white lights so it's in the brightness control mode in order to do this.

Let me know if you have any other questions!

expert reply by: Jon G

Jon G.

10/30/2025

Hey Woodrow, did the brightness adjustment on your Curt Spectrum work once you tried rotating the knob in the white light mode? Your update could make it easier for the next person setting up the same controller.