07:26 21-07-2026

Ford F-150: An Add-On Trailer Module Can Bring Back a Fixed Software Bug

Ford has flagged 315 aftermarket ITRM kits on the F-150 that can bring back a trailer lighting and brake defect a prior recall already fixed.

Ford has discovered that an additional trailer control module can reintroduce a software defect into the F-150 that a previous recall had already fixed. According to data obtained by 32CARS from the regulator’s open database, campaign 26E046 covers 315 ITRM kits for 2021–2026 trucks. The vulnerability exists in the software of every affected unit, though that doesn’t mean every module will actually fail.

If the power-up sequence goes wrong, the module stays powered but loses communication with the vehicle. The trailer then loses its stop lamps and turn signals, and on High trims, the electric brakes as well. Drivers may see a Trailer brake module fault message, rapidly flashing turn signal indicators, or a blind-spot monitoring error.

The recall covers the RL3Z-19H322-AA kit for 2024–2026 F-150 trucks and the ML3Z-19H322 module family for 2021–2023 vehicles. They were sold separately through dealers and online, and the instructions didn’t require a software update after installation. As a result, the new accessory could reintroduce a defect into a vehicle that had already received the earlier fix.

Ford identified 315 installed kits and matched them to specific VINs. Another 1,043 sold units couldn’t be traced to individual vehicles, so the real number of owners who should check their part number is potentially larger than the campaign’s formal list. The company hasn’t recorded any crashes, injuries, or warranty claims tied to the defect.

The fix doesn’t require replacing hardware: a dealer will install the updated software free of charge. Owner notification letters are expected to go out between August 3 and 7, 2026. Until the module is checked, it’s best to stop towing if a trailer brake error appears or the turn signal starts flashing rapidly.

For F-150 trucks imported into Russia, matching the model year isn’t enough — owners need to check whether the additional ITRM is installed and confirm its part number. The American campaign doesn’t guarantee a free update outside the U.S. dealer network.