Better to install a separate set of driving lights -- as long as you're courteous of oncoming traffic.

Dear Car Talk

Dear Car Talk | May 01, 2004

Dear Tom and Ray:

Hey guys, I have a '96 Dodge Dakota. When driving at night, I switch from low beams to high, and if I hold the dimmer switch in and don't release it, I get the effect of having both bulbs on at the same time, thus giving me a lot more light than if I have just the high or low beams on by themselves. Does this cause a problem in any way? Can I wire the lights to do this? I find that it really makes a difference on dark country roads. -- Jeff

RAY: Most people don't know that there are two different bulbs in most headlights -- or at least two separate filaments in the same bulb -- for high and low beams. When one is on, the other is off.

TOM: Right. The low-beam bulbs point down, in front of the car, so you can see the road right in front of you. The high-beam bulbs point up and farther away from the car so you can see farther ahead. And they inadvertently blind oncoming motorists.

RAY: So you've found a position on the high-beam switch where both filaments are lit up, and you want to know if you can make that a standing option. I suppose you can, but I think there's a danger of overheating the wiring, the switch or the bulbs. Remember, with both filaments lit, you'll be drawing twice as much current.

TOM: So, a better option is to install a separate set of driving lights. These are additional lights that are similar to high beams. They get their own wiring and a separate switch, so there's no potential for electrical problems. And when you find yourself on dark country roads, you just flick them on, and they come on in addition to your original-equipment lights. They can be very useful if you do a lot of dark-road driving.

RAY: Just two cautions. One is to get them installed on or above the bumper. If you hang them below the bumper, they can easily get knocked out of adjustment or even broken by curbs or snow banks, or Toyotas that you might run over.

TOM: The second caution is: Do not use them in traffic. We often see idiots with their driving lights on in urban areas because they think their trucks look cool all lit up like Christmas trees. These people are obnoxious morons. Don't be one of them, Jeff, OK?

Get the Car Talk Newsletter

Got a question about your car?

Ask Someone Who Owns One