2005 Super Duty Brake Control unit

[Slufoot733]

Recently my friend damaged the wiring at the 7-pin receptacle under the bumper of his 2005 F-350 Super Duty and asked me to help re-wire it. After we were all done I checked all connections and found there was only 2.74 volts on the line going to the trailer brakes. I checked this against my 2008 SD and found I had 12.45 volts. We spent two days trying to track down a short or other problem. We even tore out the instrument panel to get to the built-in brake unit just to get the pert number. Thinking the brake control unit was bad we went to the internet to find out how much it would cost to replace. That's when I found this:

18630 2005 SUPER DUTY F-SERIES - NORMAL OUTPUT VOLTAGE FOR A MANUAL APPLY FROM THE FORD TRAILER BRAKE CONTROLLER - SERVICE TIP
THE VOLTAGE OUTPUT FOR MANUAL TRAILER BRAKE APPLICATION FROM THE FACTORY INSTALLED TRAILER BRAKE CONTROLLER ON 2005 F-SUPER DUTY VEHICLES IS IN TWO DIFFERENT RANGES, BASED ON BUILD DATE. THE NORMAL OUTPUT VOLTAGE FOR A FULL MANUAL APPLY (MANUAL ACTIVATOR LEVER SLID FULLY TO THE LEFT, GAIN SETTING OF 10, VEHICLE NOT MOVING) IS 1-3 VOLTS ON VEHICLES BUILT BEFORE 3/23/05, AND IS GREATER THAN 10 VOLTS ON VEHICLES BUILT AFTER 3/23/05. BRAKE PEDAL BASED OUTPUT FROM THE CONTROLLER IS THE SAME REGARDLESS OF BUILD DATE. DO NOT REPLACE THE CONTROLLER IF IT IS PROVIDING VOLTAGE OUTPUT IN THE CORRECT RANGE BASED ON BUILD DATE. REFER TO SECTION 206-10 OF THE WORKSHOP MANUAL FOR FURTHER INFORMATION.
EFFECTIVE DATE: 05/26/2005

So, after reading this we did a test with him driving and me sitting in the bed with a multi-meter. He was traveling at 15 mph and when he applied the brakes I got a solid 12+ volts at the receptacle. After all that work and we find there was nothing wrong beyond the damaged wires.

I wanted to post this for anyone who might run into this issue. It seems that this condition existed on all 2005 Ford Super Duty trucks until March 23, 2005. After that date they changed the function of the unit to output 12+ volts standing or moving. If we hadn't found this info on the internet we would have replaced the brake unit and I am sure nobody who sell them would step up and say "oh, that's they way they are supposed to work prior to 3/23/05".

Just a note of info for anyone who might run into this problem.

[Fire5er]

Great info. Thanks!

[JandC]

Thanks for posting that. It is the type of repair that would drive you nuts!

[WaltBennett]

X2 on driving one nuts (and bolts, screws, etc.)!

[1retired06]

yup, we found brake controller did not activate at the under 5 MPH range on our 2005.