04 Ram 1500 - Factory 7 Pin Blue Wire Mystery

[Cloudfeather]

I'm waiting for a dump trailer to be built for me, so I'm getting all my ducks in a row with the trailer wiring and whatnot.

Everything seems to be in order aside from the brake control. The vehicle has the factory tow package with the 7 pin plug. I installed the Tekonsha Prodigy 2 controller, along with the Tekonsha wiring harness that goes to the factory plug under the dash. I figured it would all be plug and play, but I guess I was wrong. The unit powers up just fine and seems to be in working order.

I'm using one of the plug in LED testers at the rear of the vehicle and the BK indicator is not lighting up. Upon doing some research, I found the infamous blue wire bundle near my battery. It has a red and white wire, then splits off to the blue wire. The fuse attached is fine and there's no corrosion or any damage to the bundle. The red goes to the battery and the white, I'm assuming is a ground.

I read that you have to run the blue lead through the fire wall and attach it to the blue wire coming from the back of the brake controller. When I did this, and checked the tester, the BK will intermittently flash. If you take the blue lead and hot it directly to the battery, the BK light comes on and stays lit.

What am I missing here? I'm fairly certain that the blue shouldn't be hotted directly to the battery. Any help would be appreciated.

 

[MikeT]

I don't know how much help this post is going to be, but I'm going to try to help. I have the same brand controller and their wiring harness on my 2500. I installed the same as you did, the only difference is I tested it with an actual trailer, like you had hoped, mine was in fact plug and play. I didn't need to do any messing with other wires etc. If you know someone with a trailer with brakes that you could attach to for 10 or 15 minutes you should be able to confirm that either all is well or you need to do some amount of wiring adjustment. I believe that somewhere I have a wiring diagram for how the trailer wiring should be done with a controller and trailer brakes. I'll start digging around for that information when I get a chance. (Unfortunately that information has to have survived about 8 years and two moves so good luck to me.) As I recall thought there should be +12 volts going directly to the controller and the controller adjusts the amount of voltage going to the trailer brakes based on the settings of the controller and the amount of deceleration sensed by the sensor in the controller. So not much deceleration (stopped) and unknown controller setting may be causing very little power to trailer brakes.

Mike