You can simply unplug the temp sensor in the head and it will run anytime the ignition is switched on. Plus, I made an adapter plug that allowed me to turn it on at will. However, Jim makes a good point. A properly operating system will operate the fan the way it was designed. If you want to "trick" it to work more, check out JimF's webpage and get or make one of his units. I have resigned myself to letting it work the way it was designed.....for now!