Akray

I had this problem with a couple of trailers on my 13, now with my 14 I just picked up a 2013 enclosed trailer yesturday and the tbc won't recognize the trailer. Lights and all work, but no brakes. Says is not connected. Also so no one asks yes I installed the fuse and relay when I first purchased the truck

Feathermerchant

The fuse and relay are for switched power to the trailer. Nothing to do with recognizing trailer. If the trailer has brakes, connecting them to the truck completes the circuit so the truck 'knows' they are there. If the trailer brake circuit is open, the truck will act as if the trailer is not there and you will have no trailer brakes. You can verify the trailer brakes by manually applying them from the truck cab. My guess is you won't have any.

Akray

I've had this problem before I just forgot what the deal was, I'm looking for other people who have had the problem. The trailer will work fine for aftermarket tbc, but not the stock one.

packplantpath

For me it is always incomplete connection at the plug or a bad ground.

Akray

Yeah it's weird, must be a ground because now it shows slight brake power on the dash but still doesn't say it's connected

Weird. Also there's a couple wires in the harness I can see under the batter box that sent hooked up. But it's -25 right now to cold and brittle to do anything. And I'm 350 miles away from home

A7B2FX4

For me the problem was the inline 30amp fuse on the trailer battery charging wire. Had a intermittent connection causing the trailer disconnect msg AND either no trailer brakes or very weak response. Sometimes the latest technology is too good.

Feathermerchant

From the manual (2011):

TBC System Message Center Messages and Displays

The IPC message center displays the gain setting and relative braking power during a braking event. The message center also indicates trailer connectivity and trailer wiring faults. The following message center messages pertain to the TBC system:

NO TRAILER — This message is displayed whenever the ignition is cycled from OFF to RUN without a trailer connected to the 7-pin trailer connector.
TRAILER CONNECTED — This message is displayed when a correct trailer connection at the 7-pin trailer connector has been made during a given ignition cycle.
OUTPUT — When the vehicle brake pedal is applied, or when the manual control is activated, bar indicators illuminate in the message center to indicate the amount of power going to the trailer brakes relative to the brake pedal or manual control input. One bar indicates the least amount of output with 6 bars indicating maximum output.
TRAILER DISCONNECTED — This message is displayed and accompanied by a single chime when a correct trailer connection was made and then a disconnection has been sensed during a given ignition cycle. This message is also displayed if any of the following occur:
the 7-pin trailer connector becomes disconnected while driving
an intermittent open circuit occurs in the vehicle wiring from the TBC module to the 7-pin trailer connector or the trailer wiring
during manual activation using the manual control lever without a trailer connected (accompanied by a single chime)
TRAILER BRAKE MODULE FAULT — This message is displayed and a DTC is stored when a fault is detected by the TBC module.
WIRING FAULT ON TRAILER — This message is displayed when the trailer brake output circuit is shorted to ground or shorted to voltage. A DTC sets in the TBC module indicating which circuit fault was observed. It is important to determine if a trailer was connected when this message was displayed. If this message is only observed with a trailer connected, the concern is related to the trailer wiring and not the vehicle. If this message is observed without a trailer connected, the concern is with the vehicle wiring from the TBC module to the 7-pin trailer connector.
TBC FAULT — This message is displayed if the Instrument Panel Cluster (IPC) is receiving communications from the TBC module, but has not been configured for a trailer brake system. If the message center displays TBC FAULT and there are no DTCs stored in the TBC module, follow the steps in Programmable Parameters to verify and/or modify the TBC module programmable parameter in the IPC .

So like my post earlier, The trailer charging circuit and fuse have nothing to do with the trailer brakes or faults detected by the system. It is only looking at the trailer brake circuit.

A7B2FX4

My post earlier did not refer to any wiring or fuse on the truck. It was the battery charging fuse on the trailer. Neither Ford nor the trailer dealer could figure it out. Of my six trucks the 3 with the Ford TBC would show trailer disconnect at times and weak to 0 brakes. The 3 older trucks with aftermarket TBC never had a problem.

Akray

The stock tbc controllers are way to sensitive!

Akray

Found all wiring was broken off the back of the drums, rewired and now everything works