Ok......When I turned of my car, I was about 190*, went to the store about 30 minutes to an hour. Got back in started it and it was at 210. So I wired up the low fan to a switch. Made it work, now I did the same thing. turned the car of at 190 left it alone but now with the switch on. This time it was around 18o-185. So It does have a good affect. I hooked it up with a fuse that way it could pop it if it gets to hot or something goes wrong with the wiring