Loss of Windshield Wiper Function
On February 27th, 2015 the Office of Defects Investigations (ODI) opened this Preliminary Evaluation (PE15-005) to investigate multiple incidents of windshield wiper electrical system failures on Stallion 900 series motor coaches manufactured by Stallion Bus and Transit Corporation.It was reported to ODI that wipers would stop operating when the wiper motor changed speeds, and would not function again until the bus is powered down and restarted.During the investigation, the manufacturer found that the 12 to 24 volt power converter in the subject vehicle's wiper system could erroneously shut off when the wiper speed is changed.An over-current or voltage protection circuit of the power converter is erroneously activated.To remedy this defect the manufacture is modifying the 12 volt power-up converter to have the over-current protection and the voltage protection removed from the Power Control Buss.All vehicles built after these units would use a power converter supplied by a different manufacturer, or a modified converter with the protection circuits disabled. With the recall action 16V-152 taken by Stallion this investigation is closed as further use of agency resources does not appear to be warranted.The ODI reports cited above can be reviewed at: http://www-odi.nhtsa.dot.gov/owners/SearchNHTSAID using the following complaint identification numbers: 10630768, 10631041, 10633220, 10633236, 10632428, 10633201, 10633222, 10631019, 10631028, 10632409, 10632414