Defect
On certain vehicles, a software problem with the integrated trailer module (ITRM) may cause the trailer lights not to work when towing. This problem could also cause the trailer brakes not to work on certain vehicles. Note: This problem would cause a "Trailer brake module fault" message to be displayed and turn signal telltale to flash rapidly. This recall also affects certain Super Duty incomplete vehicles.
Safety Risk
Trailer lights that don't work could make the vehicle less visible and cause following drivers not to recognize that the vehicle is braking or intends to turn or change lanes. These issues could increase the risk of a crash. Additionally, a loss of trailer brakes could increase the risk of a crash.
Remedy
Ford will notify owners by mail and send a wireless over-the-air software update to eligible vehicles to update the ITRM software. Alternatively, you may schedule an appointment to have the update performed at a Ford dealership.