Trailer brakes issues

trail-explorer wrote:
IBC applies trailer brakes in total and complete proportion to the amount of truck brakes being applied, because it's tied in to the hydraulic system and senses brake fluid pressure.

Check all the connections between the brake assemblies and the wiring on the trailer. Some manufacturers use some pretty shoddy wiring techniques such as Scotch Locks or even WIRE NUTS!

I'd remove all splices and redo them with heat shrink insulated splice crimps.

Better proportional controllers such as the prodigy P2 and P3 apply power to the trailer brakes also based simply on the fact that you step on the pedal. The "increase" in power to the trailer brakes is largely influenced by the rate of decel. They also have the ability to customize the initial level of "boost" when you first step on the pedal.
I use a prodigy on one of our trucks, and it works well. We have the IBC in the F-350, and it too works well. The main difference I see is the Ford IBC is somewhat smoother in it's application of the trailer brakes. My "opinion" is that part of the reason it is smoother is that it is ramping up power to the trailer brakes with a slight delay, so I do not "feel" the grab of the trailer brakes initially, like I do with the prodigy and it's boost feature engaged. With boost on the P2, I feel the trailer immediately give a tug when I first hit the pedal. And I can see it on the display on the controller as well.

I agree with the above quote that I would go thru all the electrical connections first of all. Just as general idea, I would be more suspicious of bad electrical connections on a trailer than I would of a factory fault with the truck.