Maybe this is a stupid question. I have the oem brake controller in my 19 f150. Are the trailer brakes triggered by the brake pedal ? Or some sort of gyro.or another way?

I believe it is all brake pedal. But I told someone i keep my gain at 6-8 and he tells me I'm dragging my trailer brakes? If I am it's very hard to tell.
back in the day I had an aftermarket brake controller that had to be mounted at the correct angle for the ..gyro? and the brakes would definitely drag if I turned the gain up.

 

They shouldn’t be dragging hmm.

Take the gain down to where you can’t feel them, then up to where it pulls the truck when braking, then back off one or .5 level.

 

Trailer brakes are triggered by the ABS unit, ECM, and brake pedal. The attachment will explain more.

 

Thanks!