Updated Freightliner Service Bulletin for Updated ULB Control Unit for LED Headlamps

Bulletin number

SB54-331

Component

Electrical system

Summary

Updated Freightliner Service Bulletin for Updated ULB Control Unit for LED Headlamps. This bulletin replaces the version dated July 30, 2020. Information about a reman part has been added. New Cascadia vehicles with light emitting diode (LED) headlamps built from January 1, 2017 through February 17, 2020 may experience intermittent disabled headlamps due to an issue with the universal light ballast (ULB). The LED headlamps can turn off if the supply voltage drops below approximately 9V. This low voltage commonly and momentarily occurs when cranking the engine on a vehicle with batteries that are not fully charged. The momentary low voltage may cause the electronic ULB control unit to malfunction. The ULB may not resume normal function until the power supply to the headlamp is disconnected.

Owners of these vehicles have filed 10 complaints in the electrical category.