Why aren't headlights designed to shut off when you turn off the ignition?

Dear Car Talk

Dear Car Talk | Jun 01, 1999

Dear Tom and Ray:

Can you tell me why car makers don't connect the headlight switch to the ignition switch? Every morning or after a heavy rain, you drive into any parking lot and see a dozen cars parked with the headlights on, resulting in dead batteries and frustrated motorists. -- Harold

RAY: Well, Harold, this is due to a concerted lobbying effort by the Battery Manufacturers of America and the International Tow Truck Drivers' Union.

TOM: There's no good reason why headlights don't go off when you turn off the ignition key. And a number of cars have been doing it this way for years -- BMW, Volkswagen, Volvo and Audi come to mind. Although some of them leave the parking lights on, which can drain your battery just as easily if left on overnight.

RAY: Other cars, like certain Toyotas, turn all of the lights off when the ignition is off and you open the driver's door. And that's a good solution, too.

TOM: I can't think of a reason these days why you would want your lights on without having the key in the ignition. So it seems like a feature every car should have.

RAY: It requires a little bit more wiring and one extra relay, but cars are so complex these days that one more relay is hardly going to matter.

TOM: So we're with you, Harold. Lights off with the ignition! You have the placards made, and we'll organize the march on Detroit.

Used cars can be a great bargain, and reliable, too! Find out why by ordering Tom and Ray's pamphlet How to Buy a Great Used Car: Things Detroit and Tokyo Don't
Want You to Know. Send $3 and a stamped (55 cents), self-addressed, No. 10 envelope to Used Car, PO Box 6420, Riverton, NJ 08077-6420.

?(C) 1999 by Tom and Ray Magliozzi and Doug Berman
Distributed by King Features Syndicate, Inc.

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