Crusty's Curious Conundrum

Sep 17, 2007

RAY: One winter, I remember, an anxious customer called near the end of the day and needed help. She had lowered her electric window to pay a bridge toll and now it wouldn't go back up. She was getting nervous because it was one of those lousy days we get here in New England where it's starting to get misty and that stuff was going to freeze overnight with the window open. It was going to be ugly.

Anyway, Crusty told her to come on in, he would do what he could. Either it would be something simple like a fuse, or something more complex and expensive (he hoped!), and she'd have to leave the car overnight.

So at ten minutes to five she arrives and Crusty tells her to pull into one of the service bays. "What do you want me to do?" she asks. "Should I open the hood so you can check the fuses? I think they're under the hood."

"No," Crusty says. "That's all right."

"Should I turn the lights off?"

"No," Crusty says. "That'll be all right."

"Should I turn the engine off?"

"No, that'll be all right," he says. "Just leave everything just the way it is."

Crusty stands ten feet from the car and very calmly he asks her to try the window in question. Of course it doesn't work.

"Ok," Crusty says, "turn the lights off, turn the engine off. You'll have to leave the car overnight. I'll have Mad Dog give you a ride home. He's living in a junkyard near your house. I'm pretty sure that you'll need a new electric motor. Or maybe a window regulator or maybe both. Yippee!"

"How could you know that?" she asks. "You never even touched my car."

And that's the question. How did he know?
RAY: What Crusty saw is that --

TOM: The lights dimmed.

RAY: Exactly, her lights dimmed and they dimmed a lot, and they wouldn't have done that if the fuse were blown, or the switch in the door were bad. If there was an open circuit the lights wouldn't have done anything.

TOM: No.

RAY: But he saw them dim, and he knew from his vast years of experience --

TOM: Yes indeed.

RAY: -- that, you know a motor that can't turn draws a lot more current than one that can turn. In fact, if he had asked her, he could have said, try the window that works, and he could have compared, because an electric motor that can't turn is not producing something called counter EMF and, as such, draws a lot more current, and if it draws enough it'll blow the fuse eventually. But she did not have a blown fuse. When he saw those headlights dim, he knew she was done for, and he knew a boat payment was forthcoming. Anyway, so who's our winner?

TOM: The winner this week is Frederick Eames from Delmar, New York. And for having his answer selected at random from among all the correct answers that we got, Frederick will get a 26-dollar gift certificate to the Shameless Commerce Division at, with which he can get our four CD set called, Four Perfectly Good Hours.

RAY: Hm.

TOM: As the name implies, these are four of our favorite shows in their complete one hour eminently lousy original form. And that four CD collection is yours, Fred, for being this week's puzzler winner. Congratulations.

RAY: Oh you lucky devil.

Get the Car Talk Newsletter