wiring certainly can fail without any warning of any kind. IF you had voltage detection on the motor, likely you'd have seen dips in voltage as you were using the window or spikes in ampdraw, or slowdown of the motor from bad and failing damaged wire...
no monitoring of the motor is in place though.
it just stops working one day... it's a fatigue failure.
household wiring is pretty stable in comparison. it usually fails from heat/connections, or straining motors...

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!