Should Curt Spectrum Brake Controller Have Lights on Display Without Trailer Connected

Updated 12/22/2025 | Published 10/08/2024

Question:

Just installed 51170 Spectrum trailer brake controller with 51525 Quick Plug harness into my 2022 LTD Chevrolet Silverado 1500 Trail Boss. Everything seemed to go smoothly and I seem to have the brightness, brake pressure and sensitivity settings, but I get no blue lights when the pickup is started or when the brakes are applied? Is that normal or do I have an issue? From what I am seeing online I think there should be blue lights at startup and when the brakes are applied no trailer. I have not hooked up a trailer yet to test. Thanks

asked by: Matt

Expert Reply:

Hey Matt, the Curt Spectrum brake controller part # C51170 should show blue lights on the edges when there is no trailer connected so your not having any lights at all would indicate that you have a wiring issue for the brake controller. The black wire needs to run to a power source and the white to a ground. I know you used a custom fit install harness so there's chance it's maybe not seating properly so I'd check that and then also check to make sure no fuses blew. If a trailer is nearby that you can connect to I would try that just to see if anything changes.

expert reply by: Jameson C

Jameson C.

12/22/2025

Hey Matt, what ended up happening after you checked the wiring and fuse on your Spectrum brake controller? Did connecting a trailer make any difference with the blue lights? Your update could help others troubleshooting the same setup.