When I was a child I believed that the indicator for the temp. of the car was actually the temp. of the key. Based on the illustration of the thermometer I thought it was a key.
A childhood belief about cars

others believed things like this
- When I was 6 or 7 years old, I absolutely believed that if a thermometer broke--the world would end. — Suzi
- I used to think that when a movie was 'based on a true story' it was happening for real then and there— Tom
- i used to think that "the king and i" was a musical based around the life of priscilla presley— erin
- I used to believe that spaghetti grew on trees, based on a pasta commercial from the 70s.— Dianne
- I always thought that the Hulk was based of Hulk Hogan. — Vijay
- Based on that memorable scene from the "Wizard of Oz," I used to believe that people died from shrinking!— Julie