Why do TT brakes work on Tacoma but not F150?

[09KZMXT266]

Long story short, I bought a TH to pull with my Tacoma. Everything works fine, but I wanted a bigger truck to pull it. So, got a new F150 and the everything works but the brakes. When I manually activate the integrated brake controller, I get a "trailer disconnected" pop up on my screen. I had the dealer investigate and they say the truck is fine. Just to make sure I wasn't crazy, I picked up the TH last night with the Tacoma and again everything worked. Plugged the 7way into the Ford and still shows trailer disconnected. I want to troubleshoot, but not sure what to start with?

[eric1514]

If every other function works, lights, blinkers, etc. and the Ford techs have said your truck and its controller are working properly, then I would say everything is wired correctly. What is likely happening, is that the new ford controller is not supplying as much current as your old controller was per pedal travel and you need to up that if possible with some sensitivity adjustment, or adjust the brakes in the trailer a little tighter.

Eric

[RoyB]

They also make a nifty 7-way trailer connection test plug that has small LED lights on it that come on showing your trailer connector is working properly. You might find one at a auto parts place. ETRAILER has them



I have one in my RV TOOL box...

Roy Ken

[RoyB]

My 2010 F150 did not work either until I plugged in the fuse and relay. I guess you got them plugged into the correct position. I found my fuse and relay in the glove box in an unmarked envelope with no instructions what they were for haha.. Finally read something in the manual about needing the fuse and relay. This also means you have to have the ignition key turned on as well when using the brake controller.

Mine worked just fine after putting in the fuse and relay but I also discovered another feature I don't like that being using the pedal brakes doesn't engage the trailer electric brakes when you speed is less that 10MPH or so. I have to use the slider lever if I want to hold the trailer brakes on at a stop sign on an incline. I also think all of those connections have an internal fuse in the truck fuse panel for the trailer lights as well. Check the manual

Everything is disconnected on mine when my ignition key is OFF after it times out. I kinda wish I still had my P2 controller haha..



Roy Ken

[skipnchar]

ONe truck or the other may not be correctly wired and the trailer MAY have been changed to match improper wiring. Go through the connection with a spec sheet to be sure wires are in the correct order. Ford would usually use a "factory set" instrument to check your trailer plug so if they used that simple 'plug in tool" it's not likely the problem is with the Ford but if they checked it manually, it could still be the problem.
Good luck / Skip

[09KZMXT266]

YakFishMo wrote:
Have you checked to see if the fuse is installed and good for the brake controller? I know when I had an 09 F-150, I had to install a fuse and a relay. It was supplied by Ford, but not installed.

Yes, fuse and relay installed on day one. Truck was at dealer all day this week being diagnosed by the Ford electrical techs. They say couldn't find anything wrong.

[YakFishMo]

Have you checked to see if the fuse is installed and good for the brake controller? I know when I had an 09 F-150, I had to install a fuse and a relay. It was supplied by Ford, but not installed.

[Mark_Heisler]

sound like no power to the brake controller
does all the other stuff work like lights and turn signals?
take a test light and put it on the ground of your 7 way plug and then touch your brake controller pin and see if it lights up or put power to your controller.the controller should light up in the truck and when you step on the brakes your test light should light up

[09KZMXT266]

I will add that I notice when pulling with the Tacoma that I can set the controller to 12 and not lock up brakes on trailer. Should they lock up set that high?

[09KZMXT266]

eric1514 wrote:
Do all the other functions, i.e. running lights, turn signals, brakes lights all function correctly?

Get a volt meter and verify at the trailer connecter that the Ford is putting out voltage at the correct pin when someone steps on the brake pedal.

Then check to see that that pin corresponds to the pin on the trailer harness that runs to the brakes.


Eric

Yes, everything works except the brakes when connected to the F150.

[eric1514]

Do all the other functions, i.e. running lights, turn signals, brakes lights all function correctly?

Get a volt meter and verify at the trailer connecter that the Ford is putting out voltage at the correct pin when someone steps on the brake pedal.

Then check to see that that pin corresponds to the pin on the trailer harness that runs to the brakes.


Eric