The tab on the rear window defogger usually folds down when you're cleaning the interior of your car. But sometimes it gets stuck, and won't fold back up. Here's how to fix it: 1. Grab a blunt object like the end of a pen. 2. Stick it in the tiny hole on the tab. 3. If your rear window defogger is broken, here’s a quick fix. Simply remove the rear window from the car, and then remove the rubber strip that’s on the outside of it.