Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Symptom Chart: Trailer Brake System
2021 Ford Edge SE, 4WDSECTION Symptom Chart: Trailer Brake System
WARNING: This page is about a different car, the 2018 Ford F-550 Super Duty, 2018 Ford F-450 Super Duty, 2018 Ford F-350 Super Duty, and 2018 Ford F-250 Super Duty. However, it is still accessible from the selected car via links, so may be relevant.
Diagnostics in this article assume a certain skill level and knowledge of Ford-specific diagnostic practices. REFER to: Diagnostic Methods .
| Condition | Possible Sources | Actions |
|---|---|---|
| A module does not respond to the diagnostic scan tool | Fuse Wiring, terminals or connectors Communication network concern TBM |
REFER to: Communications Network . |
| The trailer brakes are inoperative | Refer to the Pinpoint Test | GO to Pinpoint Test A |
| The trailer brakes are always engaged | Refer to the Pinpoint Test | GO to Pinpoint Test B |
| The message center displays TRAILER WIRING FAULT | Refer to the Pinpoint Test | GO to Pinpoint Test C |
| The message center intermittently displays TRAILER DISCONNECTED or TRAILER WIRING FAULT while towing a trailer | Refer to the Pinpoint Test | GO to Pinpoint Test C |
| The message center displays TRAILER BRAKE MODULE FAULT | Diagnostic Trouble Codes (DTCs) present in the TBM | RETRIEVE and RECORD the Diagnostic Trouble Codes (DTCs). GO to DTC Chart: Trailer Brake Control Module (TBM) . |
| The message center displays TRAILER BRAKE MODULE FAULT when the vehicle is not equipped with a TBM | Incorrect IPC configuration | CONFIGURE the IPC car configuration parameters. REFER to: Module Programming . |
| No power at 7 way power/charge wire | Fuse Wiring, terminals or connectors Communication network concern TRM |
REFER to: Trailer Lamps . |
| The message center displays TRAILER CONNECTED when no trailer is connected | Refer to the Pinpoint Test | GO to Pinpoint Test D |
| The message center does not display a TRAILER CONNECTED message when a trailer is connected | Refer to the Pinpoint Test | GO to Pinpoint Test D |
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.