Installing a 7-Way Connector and Brake Controller On a 1988 Ford Bronco II for Towing

Question:

I am planning to purchase tear trailer with electric brakes and need to know what kind of wire harness to purchase and how to install. The Bronco has the towing package and a factory installed hitch but no evident wiring near the hitch. Can you assist?

asked by: Edmond C

Expert Reply:

To tow a trailer with trailer brakes you will need a 6-Way or 7-Way connector depending on which style of connector is on the trailer you will be purchasing. I would recommend going with the 7-Way connector, which can be used with an adapter, item # 47549, if the trailer has a 6-Way connector installed on it.

You will need a 4-Pole Hardwire Kit Including Circuit Tester, item # 18252, and a Brake Controller 7 & 4 Way Installation Kit, item # ETBC7, for this installation. Even though your Bronco II has the towing package, there is no wiring at the rear of the vehicle for towing that is factory installed.

You will need to use a circuit tester, included, to find the circuits needed behind the vehicle tail lights to install the 4-Way connector. Once the 4-Way is installed and working properly, you will need to plug the connector into the connector on the adapter included with the ETBC7 kit, and then run wiring for the brake controller and power wires to the front of the vehicle.

I would recommend the Prodigy brake controller, item # 90885, for your application.
Wiring for the brake controller is as follows:

White wire goes to suitable vehicle ground, such as the negative battery terminal.
Blue wire goes to the blue wire on the 7-Way connector at the rear of the vehicle and is the brake feed.
Red wire goes to the stop light switch wire, that goes hot only when the brakes are applied, behind the brake pedal switch under the dash.
Black wire goes to the positive battery terminal through the 20 amp circuit breaker.

Finally, the 12 volt power wire for accessories on the trailer is wired from the vehicle battery to the black wire on the 7-Way connector at the rear of the vehicle. A 40 amp inline circuit breaker is used to protect this circuit.