The investigation began in April 2016 after the agency received reports describing windshield wipers that intermittently failed to operate, causing a loss of vision and increasing the risk of a crash, according to an NHTSA Office of Defects Investigation report made public April 7.
None of the trucks has been recalled, NHTSA said.
An NHTSA investigator wrote that the preliminary probe has been upgraded to an engineering analysis that will include a study of peer vehicles “to understand how they perform relative to the subject vehicles.”
NHTSA said several of the reports from the field alleged multiple vehicles experiencing the failure and that multiple failures happened on the same vehicle. There were indications that the windshield wiper problem was resolved once the wiper motor was replaced, NHTSA said.
ODI said in discussions with Daimler, the OEM that manufacturers the Cascadias, it learned that the company had received four complaints, 12 field reports and 1,852 warranty reports involving the alleged defect on the subject vehicles.
“ODI was also made aware of a crash due to wiper failure during a rainstorm,” the NHTSA report said. “The driver alleged he switched the wiper speed from intermediate to high, and the wiper stopped working. During the loss of vision event, he lost control of his vehicle, hitting an embankment on the passenger side. The owner of the truck stated that after towing the vehicle back to their property, the function of the wipers was tested and they were found not to operate.”
A Daimler Trucks North America spokesman said the OEM is fully supporting NHTSA with its investigation, and that it takes a “proactive” approach to vehicle safety and “thoroughly investigates all known issues.”
According to the NHTSA report, Daimler said it collected wiper motors from vehicles that allegedly had wipers fail and bench-tested them, but could not duplicate the problem.