NHTSA Complaint #10275222 — 2009 KENWORTH T800

A TRACTOR UPDATE PROGRAM WAS INITIATED BY KENWORTH EARLY IN 2009 THAT INVOLVED THE 2008 T-800 TRACTORS. THE UPDATE REQUIRED THE INSTALLATION OF A 150 A "MEGAFUSE" INTO THE MAIN POSITIVE CONDUCTOR SUPPLYING ALL TRACTOR ELECTRICAL POWER (NOT TO THE STARTER MOTOR SOLENOID). SINCE THE "MEGAFUSE" WAS INSTALLED INLINE, OPENING OF THE FUSE EFFECTIVELY DE-ENERGIZED ALL ELECTRICAL COMPONENTS IN THE TRACTOR INCLUDING THE ELECTRONIC CONTROL MODULE (ECM) RESULTING IN IMMEDIATE ENGINE SHUT DOWN. FURTHER, ALL SIGNAL, WARNING, VISIBILITY AND HEAD LIGHTS CEASED OPERATION. MORE IMPORTANTLY (AND THE REASON FOR THIS REPORT), WITH IMMEDIATE SHUTDOWN OF THE DIESEL ENGINE, ALL POWER ASSISTED STEERING CAPABILITIES ARE ELIMINATED. WITHOUT POWER ASSIST, A TRACTOR BECOMES DIFFICULT TO CONTROL, AND MAY RESULT IN A CRASH. WE INVESTIGATED JUST SUCH AN OCCURRENCE FOR ONE OF OUR CLIENTS. HISTORICALLY, OUR TRUCKING COMPANY CLIENT HAS NOW RECORDED TWO SUCH ELECTRICAL FAILURES WITH ONE RESULTING IN A CRASH. THE FIRST OCCURRENCE HAPPENED WHILE BACKING INTO A LOADING DOCK AT LOW SPEED. THE SECOND OCCURRED WHILE TRAVELING ALONG A NORTHERN ONTARIO HIGHWAY CURVE AT NIGHT. THE SECOND FUSE FAILURE RESULTED IN A CRASH AS THE DRIVER COULD NOT NEGOTIATE THE CURVE IN THE DARK, WITHOUT THE POWER ASSISTED STEERING (FAR NORTHERN ONTARIO). THE MEGAFUSE IS HOUSED WITHIN THE KENWORTH BATTERY BOX, LOCATED IMMEDIATELY BEHIND THE LEFT SIDE FUEL SADDLE TANK. AT PRESENT, WE ARE INVESTIGATING THE CAUSE OF THE MEGAFUSE OPENING (FAILURE). PRELIMINARY HYPOTHESIS INCLUDED INTERMITTENT ELECTRICAL FAULT(S) WITHIN THE MAIN SUPPLY CONDUCTOR OR MECHANICAL FAILURE OF THE MEGAFUSE DUE TO VIBRATION DAMAGE. ASIDE FROM THE FAILURE MECHANISM OF THE FUSE, IT IS OUR ENGINEERING OPINION THAT A FUSE THAT NULLIFIES THE POWER STEERING SYSTEM IS DANGEROUS TO THE HEALTH AND SAFETY OF THE TRACTOR OCCUPANTS AND OTHERS THAT MAY COME INTO CONTACT WITH A MISDIRECTED TRACTOR-TRAILER COMBINATION. *TR