F150 trailer brake setting

6.5 is where I've been at with two different trailers. It will vary according to size of trailer and how your WDH is setup.

I have a 2014 F 150. I adjust it by feel. Set it light and increase it as needed.

I used the procedure from the 2015 F150 owner's manual and could never get my trailer brakes to lockup on a paved surface, so I adjusted the brake controller until I felt strong braking from the trailer brakes. I believe that the controller on my 2015 F150 is set at 7.5.

This is from the 2015 F150 owner's manual.

Use the gain adjustment (+ and -)
buttons to increase or decrease the
gain setting to the desired starting
point. A gain setting of 6.0 is a good
starting point for heavier loads.

In a traffic-free environment, tow the
trailer on a dry, level surface at a speed
of 20-25 mph (30-40 km/h) and
squeeze the manual control lever
completely.

If the trailer wheels lock up, indicated
by squealing tires, reduce the gain
setting. If the trailer wheels turn freely,
increase the gain setting. Repeat Steps
5 and 6 until the gain setting is at a
point just below trailer wheel lock-up.
If towing a heavier trailer, trailer wheel
lock-up may not be attainable even
with the maximum gain setting of 10.

Page 265 gives the "right number". Each truck/trailer combo is unique based on the trailer's brake adjustment and wear.

Yes, the setting will be independent per setup. I have a 1 ton and much heavier TT so there certainly is no direct setting comparison...

I like to get on a dirt/gravel road travelling about 5-10mph and hit the manual trailer brake lever not touching the truck brakes. I expect the trailer brakes to lock up. If they don't, increase controller setting by .5 increments, testing each time until the trailer brakes do lock up on dirt/gravel. Then go test on dry pavement, away from any other road goers, and see if it feels like the truck is stopping normally, like the trailer is not attached. If you feel as though the truck is partially stopping the trailer (i.e. trailer brakes not fully responsible for stopping trailer weight) again, minor adjustment, up by .5 and test again until it feels acceptable to you.

I have a 2014 and I set it at 9 and forget it. It really is proportional to the brake pedal pressure.

If it's like my 2013, go ahead and set it on 10.

I have an F250 with that system and have towed all types of trailers. Depends on the weight of the trailer. A setting for a heavy trailer will lock up the wheels of a light trailer. Start with a light setting and work up. 3 or 4 stops and you'll find the best setting.