Ford has been monitoring certain 2021-2023 Ford F-150 trucks equipped with single exhaust systems due to potential issues with the electric parking brake. Reports have surfaced indicating an unexpected activation of the parking brake, sparking concern among owners and the automaker alike. In response, Ford’s Critical Concern Review Group (CCRG) launched an investigation to assess the problem’s magnitude and potential root causes.
The initial investigation began after Ford received troubling reports of unintended parking brake application on a 2021 model year F-150 truck. Warranty and field reports revealed signs of damage to the wiring harness housing the rear electric parking brake circuits. Such damage raised red flags, necessitating a closer look to ensure the safety and reliability of these vehicles.
Looking deeper into the issue, Ford’s team of experts discovered that the damaged wiring was a component of the rear axle wiring harness assembly. This particular harness assembly not only houses wires for the rear electric parking brakes but also serves other essential electrical components. The investigation highlighted that, in certain scenarios, the rear axle wiring harness bundle could make contact with the rear axle housing, leading to chafing of the wiring bundle.
Over time, this chafing effect could wear through the abrasion-resistant tape and circuit insulation, ultimately exposing the underlying copper wiring. The consequence of this exposure could be the grounding of circuits on the rear axle housing, which in turn could cause unintended activation of the electric parking brake. Adding to the complexity, corrosion on the rear axle housing could accelerate the abrasion process, compounding the problem.
Ford’s engineering team took the investigation further by conducting comprehensive vehicle-level testing and data analysis. The goal was to understand the implications of damaged circuits within the wiring harness bundle. They discovered that if the low side electric parking brake motor circuit experienced a short to ground, it could trigger the unintended activation of the electric parking brake, potentially leading to hazardous situations.
Ford are initiating a recall to resolve this issue. Owners of affected vehicles will receive official notices instructing them to take their vehicles to authorized Ford or Lincoln dealers for thorough inspections of the rear axle wiring harness.
During the inspection, if the technicians observe any wear on the abrasion tape covering the wire bundle, the suspect harness will be replaced with a new service harness. In cases where the abrasion tape shows no signs of wear, the dealer will take preventive measures by installing a protective tie strap and tape wrap, ensuring the wiring remains secure and safeguarded against future issues.
Ford is aware of 918 warranty and three field reports in North America for the wire chafing condition. Of these reports, 299 indicated that the electric parking brake had unintended activation, of which nineteen (19) allege electric parking brake application while driving. Ford has assigned a recall number to this campaign, which is 23S35. Additionally, the National Highway Traffic Safety Administration (NHTSA) has designated the campaign as number 23V-509.