NHTSA recall 10V637000
Equipment
Girardin MB II and 1 more
The defect
Corp. Micro bird IS recalling certain model year 1999 through 2001 girardin mb II and mb IV school buses built on ford and gm cutaway chassis from august 2, 1999, through may 31, 2001, and equipped with a trans/air TA73 evaporator. the evaporator utilizes a power resistor to regulate blower speed. Should a short occur in the "low or medium speed" circuit while the blower IS in high speed, the short will cause the supply voltage to feedback through the resistor to ground, not drawing enough current to trip the fuse.
The risk
This would cause the resistor temperature to rise to a point where it will melt and possibly ignite the plastic blower housing to which it IS mounted. the overheating can result in a fire.
The remedy
Corp. Micro bird in cooperation with trans/air will install a thermal shutdown device in series with the speed resistors. this service will be performed free of charge. the safety recall began on january 11, 2011. owners may contact trans/air warranty and service center at 1-800-673-2446.