Troubleshooting Reverse Lights Not Working on 2021 Chevy Blazer 7-Way

Updated 10/28/2025 | Published 03/01/2025

Question:

Installed this on my 2021 Blazer a month or 2 ago and finally got to use it and all lights work just fine except the back up lights. Thought maybe it was my trailer but tested the plug on the blazer and no back up lights. Can you point me in a direction to figure out why they are not working?

asked by: Logan M

Expert Reply:

Hi Logan; since the # C56326 ties into your vehicle wiring I would be checking fuses. More than likely you have a blown/missing fuse for the reverse function. I don't have a specific location for the fuse on your Blazer so you will have to look it up. The fuses will also be marked on the inside of the fuse box lid. If the fuses check out then you probably have a short and will need to work your way back testing until you find it.

expert reply by: Robin H

Curt T-Connector Vehicle Wiring Harness
(click to enlarge)

Robin H.

10/27/2025

Hey Logan, did checking the fuses on your Blazer help get the reverse lights working again with the Curt wiring harness? Knowing what fixed it could really help others troubleshooting the same issue.

Logan M.

10/27/2025

@RobinH, After checking all the fuses and all of them working fine I disconnected the wiring harness and found that the plug was getting power. So started looking at the wire harness plug and I found the pin for the revers light was folded over. Not sure if I did that when plugging everything in or was it already off a little bit and when I plugged it in it bent the rest of the way over. Just very weird that only 1 pin was bent over because if it was plugged in wired or off set a little bit it would have caused more pins to fold over. Any way I straighten the pin out and plugged it all back up and the reverse lights came on. Thank you for following up to see if I got this resolved. To be clear it was the pin on the wire harness where it connects to the 7 way plug that the trailer plugs in to. I tried to add pictures of exactly where the pin was at but it would not let me.