I found a great article on www.etrailer.com here.
Trailer Brake Controllers
An electric trailer brake controller is a device that supplies power from a vehicle to a trailer's electric brakes. There are two types of electric brake controllers - Time Delay Activated ("solid state") and Proportional ("pendulum style"). Although the controllers' methods are different, both types of controllers are very similar. Both allow the user to adjust output or braking power. Both have a pressure sensitive manual override trigger that can be used to apply the trailer brakes independent of the vehicle brakes. Both have the same wiring configuration.
Time Delay Activated
Solid state controllers are "enabled" by the brake pedal switch and apply a gradual voltage to the trailer's brakes using a Time Delay Circuit.
Advantages : Time Delayed controllers are inexpensive, have a low profile, and can be mounted on any angle (very user friendly).
Disadvantages: When towing (in most applications) with Hazard flashers on, the Digital Display will flash with the Hazard Flashers. If the Brake Control is set aggressively, pulsing may be felt in the trailer brakes. However the Pulse Preventer will isolate the Brake Control from the flashers and eliminate the flash/pulse situation.
Proportional
Pendulum Style Controllers are "enabled" by the brake pedal switch and "activated" by a Pendulum Circuit that senses the vehicle's stopping motion and applies a proportional voltage to the trailer's brakes. When properly adjusted the trailer will decelerate at the same speed as the tow vehicle. This increases braking efficiency and reduces brake wear.
Advantages: Pendulum style controllers operate well under adverse braking conditions and have a smooth braking action.
Disadvantages: Most inertia-activated controllers are bulky, more expensive, and must be mounted and calibrated level. The Tekonsha PRODIGY™ and Valley Odyssey™ proportional brake controllers are the exceptions to these disadvantages.
Wiring Configuration
Hitch Supplied Brake Controllers require 4 wire Connections:
1. Trailer Feed (usually blue) - This is the wire that supplies brake power for the controller to the 6-way or 7-way trailer connector at the back of the vehicle. Some vehicles with factory tow packages already have this wire run from under the dash to the rear of the vehicle. Otherwise, the wire is run along the underside of the vehicle and through the firewall to the desired Brake Control mounting location. To get through the firewall, sometimes a hole must be drilled. However, grommets or pre-existing holes are often available.
2. Ground (usually white) - This wire is connected from the brake controller to any reliable ground source.
3. Brake Switch (usually red) - This can be found near the top of the brake pedal. There are wires extending from the switch and using a test light, the wire that has power when the brake pedal is pressed down can be found. This wire is tapped into using a scotch lock.
4. Battery Power (usually black) - This is the connection that supplies power to the brake controller. Some vehicles with factory tow packages already have this wire run from under the dash to the battery with some kind of circuit protection. Otherwise, a wire must be run through the firewall and connected directly to the battery with an in line circuit breaker.
Generic Wiring Diagram
To provide assistance in the hardwiring of brake controllers, brake controller install kits are available. They provide the needed wire that runs the length of the vehicle to the trailer connector, as well as the trailer connector, fuses, and wire connectors. A kit is available for both 6-way and 7-way trailer connectors.
Recently vehicle manufacturers have started installing OEM harnesses under the dash. Adapters are made that will connect to the brake controller and plug into the harness. If the tow vehicle is equipped with a tow package and has a factory installed 7-Way trailer connector then a brake control adapter may be all that is needed.
Trailer Brake Controllers
An electric trailer brake controller is a device that supplies power from a vehicle to a trailer's electric brakes. There are two types of electric brake controllers - Time Delay Activated ("solid state") and Proportional ("pendulum style"). Although the controllers' methods are different, both types of controllers are very similar. Both allow the user to adjust output or braking power. Both have a pressure sensitive manual override trigger that can be used to apply the trailer brakes independent of the vehicle brakes. Both have the same wiring configuration.
Time Delay Activated
Solid state controllers are "enabled" by the brake pedal switch and apply a gradual voltage to the trailer's brakes using a Time Delay Circuit.
Advantages : Time Delayed controllers are inexpensive, have a low profile, and can be mounted on any angle (very user friendly).
Disadvantages: When towing (in most applications) with Hazard flashers on, the Digital Display will flash with the Hazard Flashers. If the Brake Control is set aggressively, pulsing may be felt in the trailer brakes. However the Pulse Preventer will isolate the Brake Control from the flashers and eliminate the flash/pulse situation.
Proportional
Pendulum Style Controllers are "enabled" by the brake pedal switch and "activated" by a Pendulum Circuit that senses the vehicle's stopping motion and applies a proportional voltage to the trailer's brakes. When properly adjusted the trailer will decelerate at the same speed as the tow vehicle. This increases braking efficiency and reduces brake wear.
Advantages: Pendulum style controllers operate well under adverse braking conditions and have a smooth braking action.
Disadvantages: Most inertia-activated controllers are bulky, more expensive, and must be mounted and calibrated level. The Tekonsha PRODIGY™ and Valley Odyssey™ proportional brake controllers are the exceptions to these disadvantages.
Wiring Configuration
Hitch Supplied Brake Controllers require 4 wire Connections:
1. Trailer Feed (usually blue) - This is the wire that supplies brake power for the controller to the 6-way or 7-way trailer connector at the back of the vehicle. Some vehicles with factory tow packages already have this wire run from under the dash to the rear of the vehicle. Otherwise, the wire is run along the underside of the vehicle and through the firewall to the desired Brake Control mounting location. To get through the firewall, sometimes a hole must be drilled. However, grommets or pre-existing holes are often available.
2. Ground (usually white) - This wire is connected from the brake controller to any reliable ground source.
3. Brake Switch (usually red) - This can be found near the top of the brake pedal. There are wires extending from the switch and using a test light, the wire that has power when the brake pedal is pressed down can be found. This wire is tapped into using a scotch lock.
4. Battery Power (usually black) - This is the connection that supplies power to the brake controller. Some vehicles with factory tow packages already have this wire run from under the dash to the battery with some kind of circuit protection. Otherwise, a wire must be run through the firewall and connected directly to the battery with an in line circuit breaker.
Generic Wiring Diagram
To provide assistance in the hardwiring of brake controllers, brake controller install kits are available. They provide the needed wire that runs the length of the vehicle to the trailer connector, as well as the trailer connector, fuses, and wire connectors. A kit is available for both 6-way and 7-way trailer connectors.
Recently vehicle manufacturers have started installing OEM harnesses under the dash. Adapters are made that will connect to the brake controller and plug into the harness. If the tow vehicle is equipped with a tow package and has a factory installed 7-Way trailer connector then a brake control adapter may be all that is needed.
