I have a 2004 F-150. With it came a relay and a wiring harness for electric brake controller. I do not have an electric brake controller. Question is: If I plug in the relay without having the controller will I have electric brakes to the trailer using the 7 pin connector?

 

no, you need the brake controller. it regulates the amount of voltage aplied to trailer. i believe the relay is for the reverse lights.

 

The relay is for the trailer charge pin...........

 

You need a brake controller as stated and the response for the Charge line relay is also correct, You also have fuses for the trailer charge line the brake controller and the trailer lights as well as individual fuses for right stop turn and left stop turn.

 

Your kit from Ford should come with a fuse and a relay. As well as a pigtail adapter with labels. All TBCs have simple instructions and the colors are always the same. For TBC wiring. White (-) Black (+) Red (From brake switch) Blue (Feed to trailer brakes.)) You may butt connect the harness and TBC or many adapters are available at your local RV dealer, or online which are vehicle specific. Locations differ too, Earlier 2ks have prewire under dash, later under HVAC duct in driver's side center console. And, they have changed shape. RV dealers sell a lot of TBCs, and usually have the widest selection in stock. The relay in your kit is for your charge line in the 7pin harness. The fuse should be for TBC power. Some years of fords already have fuses in place...or so I have seen. None usually have relay installed. The relay use, instead of a fuse is to prevent discharge of tow vehicle battery due to a parasitic drain in the trailer. In the RV world, a light left on, or a refrigerator running off propane, utilizing a weak, and bad deep cycle battery. A fused location will allow this to occur. An ignition relay protected one will not. It is preferable to have a fused brake line as if there is a failure or short in the braking system, loss of trailer brake system will immediately alert driver there is a problem and, at minimum, a visual inspection of the braking system is in order. Ignition relays are preferable with a circuit breaker. Brake circuits, and critical systems, in a simple circuit like a TBC are best fused. Keeps cost down.