I installed tow brake controller on my 99 k2500 with 454 motor. Curt "DISCOVERY" model 51120....Discounted off EBAY...Veh had pre existing wiring there from previous owner.

I have left turn, rt turn, and stop lights on my trailer that work when connected to my 7 prong typical rear plug. I have looked at instructions to verify wiring was done correctly to the controller. It appears correct.

The DISCOVERY said you are connected fine (w/o trailer connected) when you hit brakes and a red dot appears on controller screen. But when you hit brakes with trailer on the numbers are supposed to come on...With my open equipment trailer attached, and connected, the brake controller still reads the red dot....like it is not getting any signals from trailer. I towed my race car ok a couple weeks ago just with factory brakes.
When I last used trailer (February) conncted to my Durango, it worked fine..
Since I have left, rt and brakes working on the rear trailer when connected..I wonder where I could have a wiring issue...

My trailer is 1998. so it came with a I think a 5 prong I converted to 7 back then and it has not had any issues with 2 prior vehicles with tow controllers until now..
1. I have wiring issue (controller would read it digitally though on my controller if it were that-per the controller)

2. or-I have bad controller?

3. or electric brakes have issues on trailer...my little battery that operates the disconnect protection may be dead..it sat in MN below zero weather since February....
That shouldnt have any bearing?

 

Don't have any experience w/ trailer brake controllers but first thing I'd do is charge the trailer brake battery.