If you have access to a multimeter, see if the fan is getting juice at the connector. Take a reading with the engine on, A/C off. Then take a reading with the engine on, A/C on. If there is a difference, then your motor is toast.
If there isn't a difference in voltage, then your relay is toast. THen move on to your relay connections to determine if the relay is getting juice or if the ECU is toast.
C'mon men, standard troubleshooting. If you don't have a multimeter, get one.
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