Do I assume, when you described that you were driving home, that you were driving along at a reasonable speed?
Your auxiliary electric fan is only important when you're crawling or stationary in rush hour traffic. If you were driving at normal road speed, say 30+ mph, and you were overheating, that little electric fan (or even your viscous clutch main fan) are definitely NOT the culprit. The normal "ram air" of the car's velocity overwhelms any contributions of the fans. You have to look elsewhere for the cause of your overheating.