15 EL XL with factory tow package integrated brake controller is sending too much brake voltage at low speeds

[15ExpyELXL]

15 EL XL 4x4 towing my travel trailer with gain around 5 brakes are good at freeway speeds, but in town at around 25 mpg the trailer brakes are locking up, trailer is bucking, way too much trailer brake power. I have to turn down the gain to 2 or less while driving slow, then remember to turn it up when I leave town. I have a 15 F150 with factory tow package and it pulls this same trailer perfectly, with the gain set around 5. New trailer brakes were installed by me last season, full replacement except drums, including cross axle wires. I believe the trailer brakes are good. I have used a Y 7 pin adapter and pulled wires into the cab to a multimeter, and the IBC clearly has a jump in voltage with medium braking at low speeds. Has anyone else experienced this? I would like to replace the IBC in the dash but have not found good instructions for getting into the Expy dash, most info is for F150 and different dash config. Looks like I would have to pull the center console also so it's going to be a headache to parts swap.

 

[m3olsen]

@15ExpyELXL , this thread talks about upgrading to IBC and mentions that it pops in from the front. I assume that means you can do the reverse to remove it without pulling dash: https://www.expeditionforum.com/threads/2017-factory-brake-controller.36311/

 

[15ExpyELXL]

I was able to pry it out of the dash with a poly prybar, I pried from the top of the controller.