My car has a fan light that comes on when I turn the aux. fan on. It does not come on when the other fan only comes on. Look in the owners manual, it shows the location of the aux. fan light. I didn't know I had one until I read that thing. Mine didn't work either, thanks to Raymond telling me to check the relays, that is what it was. A simple Napa part. The relays are by your fuses, the little black plug in boxes.