Q: What is the purpose of testing to see if the cooling fan works

Testing to see if the cooling fan works will typically indicate a few things. It may indicate whether or not the cooling fans are coming on at the correct temperatures which may be indicated by a temperature switch that sends a signal to the cooling fan resistor. The cooling fan resistor will cause the fans to come on at a higher rate than normal when the temperature switch indicates that the temperature has exceeded a specific threshold. There is also a cooling fan relay, which provides power to the cooling fans based upon a signal directed from the computer at a specific time when additional cooling is needed. If the cooling fans are not coming on at the correct times, this can cause the temperature in the motor to fluctuate erratically as a result of them not coming on at the appropriate times or in some cases not at all.