UPDATE: Got into the car today and everything worked. The fan came on and is working normal. How strange… it wasn’t working for two days and magically it worked today. This is puzzling.
Some theories:
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ECU/ECM causing this. My car, 2007 Corolla, has a ECU recall that has not been performed. The recall is for a failing ECU that may stall the car. It’s a safety recall. I haven’t done the recall because I figured I didn’t really need to and am a bit worried that new ECU might degrade it’s performance.
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The last two days, when I started the car in the early morning (3am) in freezing cold temperatures of 30 degrees. The fan wouldn’t come on at any setting. Today, the temperature is around 45 degrees and it worked normally. Might this have something to do with it? Possibly, let me explain. The fan has slowly degraded over the years of ownership and for the last two years it’s been making a slightly audible chattering sound. It’s something I can tolerate but I knew the fan would die someday, in the near future. My guess is that the cold temperatures built some frost in the motor fan (thus obstructing its movement) and the warm temperature melted it away, so now it’s working.
Any comments?