Have a 2011 f-150 and tow an 18 foot car trailer with a 2006 roush mustang on it, while trying to set the controller to lock up the brakes i got all the way to the 10 position and they still won't lock up, it is my understanding that you go up untill the brakes lock up and then back down a number but mine will not lock up, the truck and trailer stop fine at the 10 position but is it normal not to get it to lock up the brakes while setting the controller anyone else towing have any info ?

 

That does not seem right to me. I have a 7000lb trailer that I can get the wheels to lock up. Have you checked the brakes on the trailer. The truck might be fine but a loose connection or bad magnet on the trailer or even poorly adjusted brakes could be the issue.

 

Are you trying to set the gain using the manual slide lever at about 20 MPH? My trailer weighs only half what yours does but when I slide the lever over quickly, I almost go through the windshield. Do you have the trailer brake type set to electric? If you have everything set correctly, I agree with Matt, it sounds like you have a problem in the trailer.

 

x3 look in to your trailers brakes. have you tried just the trailer no car on it? i had a TT and i never got it to lock up but there was a bad lining in the TT drum! once it was fixed it would stop on a dime at like 2.5.

 

See if your pads on your brakes are set right. There should be a slight resistance when the drum is set right. If there isn't, then you might need to adjust the drums slightly.