No wiring to 7-way plug

[TSPowell]

Need some help here. Just purchased a 2008 3500 dually. I was getting ready to remove the odessy controller that was already on the truck and install my MaxxBrake controller.
the previous owner installed what looks like an aftermarket harness to plug into the 7-way receptacle on the bumper. It had a red power wire connected to the battery (with fuse), ground and a blue wire to the brake controller and pluged into the factory 4-way. It turns converts all those into a 7-way plug. I removed this harness, now there's nothing to plug into the factory 7-way plug. Where is the factory plug on the harness??? Is there a chance it didn't come with one. There is a 4-way plug...

 

[TSPowell]

Sooooo... after a little more reading, apparently dodge made some pickups without a 7-way receptacle on the bumper. I am completely baffled that a 1-ton dually could be build without this plug, what the hell did dodge think people are going to do with this type of pickup??????!!!!!!!!
Anyway, Mopar makes an aftermarket harness to install a 7-way plug, which the previous owner did on this truck. So now I'm left with a blue wire (trailer brakes) under the dash. My dilemma is I can plug my MaxBrake into the truck under the dash (blue plug) but what do I do with this blue wire. Its pretty important that is goes somewhere.
Surely I'm not the only person that has dealt with this situation. If you have any advise, PLEASE help. I need to tow a trailer in two days.......

 

[Prairie Dog]

They made some without a hitch either.
Bizarre.

 

[TSPowell]

Wow.... I was hoping for help than this.

 

[TLane]

The blue wire to the trailer brakes must be connected to the brake controller. There *should* be a blue wire coming from the controller, it needs to connect to the blue wire that goes to the trailer brakes. I'd see if I could connect the blue wire into the blue connector under the dash, disconnect any other factory wires in the position where the blue wire goes to the controller.

 

[mwilson]

Why did you remove the add-on harness??? I think you should have left it in place if I understand what you are saying. Unhooked the existing controller and used that wiring for the new controller. I may have missed something here but it would appear that you need that.

Mike.