What is the Amperage Draw of the Dexter Electric Over Hydraulic Brake Actuator for Disc Brakes

Question:

My aluminum boat trailer with disk brakes on all three axles has a Dexter K71-651 hydraulic pump. Total weight of boat and trailer is about 7500 lbs fully loaded. My new tow vehicle is a 2015 Mercedes GL350 with factory hitch and seven pin round wiring harness and connector. Dexters information indicates that a 40A circuit is required for the center pin. The Mercedes maximum fuse for this circuit is 30A. It is not unusual for fuses to be rated about 25 in excess of the circuits actual load. Do you know the maximum ACTUAL load on this center pin? It would be quite difficult to run a another very heavy 8 GA ? wire to the battery with a dedicated fuse/breaker due to the battery location, but then I would hesitate running the risk of over-heating the existing wiring by ing a 40A fuse. I would like to consider buying a Tekonsha Prodigy RF controller for this vehicle in order to avoid any risk of damaging the innumerable computers on this vehicle! Also, do you have any suppliers that have recently added a front hitch for this model vehicle?

asked by: John B

Expert Reply:

First, the Prodigy RF brake controller # TK94FR, is not compatible with electric over hydraulic braking systems, so you wouldn't be able to use it with actuator # K71-651.

A vehicle manufacturer could have higher than needed fuses for a given circuit but that is not beneficial because that would allow the electrical device to overdraw and cause damage.

The Dexter actuator only requires a 30 amp circuit to power it unless in temperatures under 0 degrees F. Then it needs a 40 amp circuit. If you did need to run different wire you could use 10 gauge, 8 would work but is not necessary. To avoid any damage to the vehicle you would sever the wire at the back of the 7-Way for the 12 volt circuit, run a new 10 gauge wire using # 10-1-1, and attach it directly to the vehicle positive battery terminal via a 40 amp circuit breaker # PK54540. But only if the 40 amp is necessary.

But to be able to use the Prodigy RF with your 2014 Mercedes GL the trailer would have to have electric brakes and not electric over hydraulic brakes. So that would mean instead of the actuator you would need to convert the trailer over to electric brakes. And of course, on a boat trailer, it is not recommend to run electric brakes.

So instead, go with surge brakes if the trailer is not using them already. You would just need a disc brake actuating coupler. I have included a link to all of the disc brake actuators we carry.