Which Circuit Breakers in ETBC7 Kit to Use for Brake Controller and Trailer Auxiliary Power Circuits

Question:

2017 Toyota Highlander, V6, 5K tow rating, will be towing 17foot Casita travel trailer, 2650 dry weight, single axle. Question, the ETBC7 wiring diagram shows 20/30A breaker on hot lead to break controller and 40A hot lead to trailer battery. The hopkins 7 pin connector and the pigtail supplied with a Tekonsha Prodigy P2 controller has no wires greater than 12 AWG, rated at 20A maximum. Therefore, wouldnt both circuit breakers be at 20A? The 40A seems way too high. 30A to the controller also seems too high.

asked by: Dennis M

Expert Reply:

The multiple circuit breakers in the # ETBC7 7-way wiring kit include a 40-amp breaker for the trailer 12V auxiliary power circuit and the 20- and 30-amp breakers are for the 12V power feed to the trailer brake controller. The choice of which to use depends on how many total brake assemblies the controller has to power. Usually for single or tandem axle trailers the 20-amp breaker on the controller's power feed is fine, but if the trailer has three axles often the 30-amp breaker is needed.

We usually recommend using the 30-amp breaker on the controller's power circuit no matter how many axles require brake power.

expert reply by: Adam R