Vehicle report
Technical service bulletins are instructions a manufacturer sent its dealers about a known fault. They are not recalls and the work is usually not free, but they are the clearest signal of a problem the manufacturer already knows about.
TSB-23009
The engine block heater wiring was extended and spliced into the shoreline power with the battery charger on some Commercial Chassis Fire Trucks. This may cause a high amp draw on the shoreline power so here is how to fix it.
Complaint counts are reports filed with NHTSA, not failure rates. A common model collects more of them than a rare one that breaks more often.