At a glance
What can fail
The heater blower resistor's rough stainless steel blades can scrape and damage the copper connector in the wiring harness. Over time, this damage increases electrical resistance and can cause the circuit to fail completely.
What the fix does
Dealers will replace the heater blower resistor and install a new wiring harness jumper to restore proper electrical connection.
Summarized — see the official notice for exact wording, dates, and contacts.