Pretty lame answer. All true but the root cause is improper and inadequate design engineering work. Not doing a FMEA failure mode effects analysis with a multidisciplinary team with design, manufacturing, product quality, supplier quality engineers in the cross-functional team chartered by the chief product engineer.
I might further add as this could be a fire hazard a complete SHA safety hazards analysis should have been performed for this component.
Both of these happening are the direct responsibility of the Chief engineer on the project.
If all of this fails it's kicked to service engineering where they chartered to develop a fix or work around. This may or may not include issuing a service bulletin or a recall. Could be mandated or voluntary.
Key is having the resister,fan switch,fan motor,fan and wiring harness manufacturers work in a systems approach together early on. This is when you have the best opportunity to obtain the best quality, reliability and the sweet spot for reducing costs and obtaining the maximum TCO.