Preliminary Evaluation · Closed
Engine Electrical Wiring Harness Chafe
Manufacturer: Daimler Trucks North America, LLC
What NHTSA is examining
The Office of Defects Investigation (ODI) opened this Preliminary Evaluation to investigate reports of engine electrical wiring harness chafe on the subject vehicles.ODI analysis found thousands of unique harness part numbers, spanning the two generations of vehicle chassis assembled at multiple vehicle assembly plants in two different countries, with multiple sub-models, incorporating over thirty powertrain choices.Each wiring harness could contain several dozen individual wires for power, ground and communication purposes depending on the multitude of equipment options available for custom vehicle configuration. ODI identified three primary areas where a wiring harness bundle may chafe: the air compressor support bracket, the transmission case, or the coolant surge tank. In each case, the root cause was some combination of inadequate design clearance, installation variability and relative motion between the wiring harness and the point of contact, such as from vibration. The chafing could result in a range of consequences from none to various diagnostic fault codes, telltale illumination, driver warning center messages, erratic electrical component operation, difficult or no engine start condition, engine de-rate (power reduction), engine shut down, inoperative transmission gear selection, or an unexpected shift to neutral.These potential consequences vary depending on the specific damaged wire in the harness and the exact failure mode, such as intermittent short circuit…
Vehicles under investigation
Source: NHTSA Office of Defects Investigation records, updated daily. An investigation is not a determination that a defect exists; many probes close without a recall.