2008 F350.
sitting in the driveway: gain set to 10, when I squeeze the manual "levers" together the graph display completely lights up and I get 12+ volts at the trailer plug.
When I press the brake pedal I get a full graph display but only 2 volts.


Hooked up to the trailer, pushing the pedal gives very very little braking (I can turn the hub by hand),
Squeezing the manual levers the drums lock up.


Is normal? is the controller faulty ??


Nick

 

Update:
I opened the J box on the trailer, ran a 12ga wire from the brake wire, into the cab of the truck and hooked it to a DVM.
I set the gain to 8.0
at a standstill with the brake pedal floored I got .5V
at 20mph coming to a brisk stop I got 2-3 volts,
at 30-40mph coming to a brisk stop I got 4-5 volts
at 50mph I got 6-7 volts.
squeezing the manual brakes I got 10.5v at a stand still


Slack

 

The integrated brake controllers on these trucks determine their output on a # of factors.....what you have the gain set at, what speed you're doing, and how hard you're pressing the brake pedal. I'd say your findings are normal for being stopped in your original tests.

 

This is an ongoing complaint with the Ford TBC. it is perhaps the most misunderstood component ever developed. From your numbers I think your controller is working correctly. What it does at manual versus the pedal is irrelevant.

Steve