Brake Controller is Saying No Trailer When Trailer is Connected

Question:

I bought the T-harness with 7-plug for my 2018 and the oem brake controller switch to mount in dash panel. Looks great. All fuses but #24 were already in place. Filled #24 with 30A and Ford dealer enabled TBC program. Now when I plug trailer in with electric brakes I get a message “no trailer”. Gain works + and - on display, all lights and signals work but it seems nothing to brakes on trailer or battery or backup. Everything that works to 4 pole works on 7 pole but nothing more. Can’t find out why

asked by: John W

Expert Reply:

What you may try looking at is the ground connections on the brakes. Each brake should have its own separate and designated ground. It would also be a good idea to check all the grounds as a bad ground can cause any number of weird things to happen.

If the grounds are good or fixing them does not get it working properly, let me know and we can try something else.

expert reply by: Lazer S