Jim Smart
December 3, 2003

Mustang & Fords is going to do something we've never done before:dedicate an entire article to light bulbs, and other sources ofartificial light. Lighting has come a long way since our vintage Fordswere rolling off the assembly line 30-50 years ago. Headlightsespecially have improved dramatically because they light the road aheadso much better today than they did in 1963. This, all by itself, is apositive safety advance for older Fords, Mercurys, and Lincolns.

Vintage Ford aftermarket companies are concerned about your safety, andwant you to have lighting that's cool and technologically advanced. Wewant you to know all about that coolness and how to make your Fordsafer. So, we'll begin at the grille and work our way back. By the timewe reach the back bumper, we're convinced you will approach this wholelighting issue with an informed mind, ready to make an educated decisionabout your Ford's lighting.


Headlights are the most important lighting element your Ford has. Theylight the road ahead and determine your Ford's personality. How wellthey light the road is critical to your safety, and the safety ofothers.

Headlights also determine a vintage Ford's personality. The grille iswhat people see first when you arrive. When they look in the rearviewmirror, it's the only thing they see besides your smiling face throughthe windshield. A vintage Ford's grille is like a human face. It tellsus at a glance what the ride is all about. For example, originalsealed-beam headlamps speak of a conservative approach, of nostalgia. Onthe other hand, composite headlights make an older Ford look high-tech.They bring a 20th century ride into the 21st century. European cars, forexample, have always used composite headlamps in great numbers, datingback to when all you could use in the United States was a DOT-certifiedsealed-beam lamp. Today's aftermarket offers us all kinds of compositeheadlamps for older Fords that are street-legal. Visit your internetsearch engine and examine your options. Key in "Automotive Lighting" andgo wild.

When we think of a sealed-beam headlight, we think of the fragile glassenvelopes that were installed in our Fords from the factory. Thoseglaring beams had personality. They were certainly American, but theydidn't do much for lighting the road ahead. They were a soft, off-whitebrown tone in low beam. And touching the high-beam switch didn't give usthe greater levels of light we needed.

A sealed-beam headlamp's construction and function are easy tounderstand. Like the light bulb in your desk lamp, and not muchdifferent from Thomas Edison's first working light bulb of more than 100years ago, a sealed-beam headlamp sports a filament, or filaments, in avacuum envelope void of air. In this vacuum, there is no oxygen tosupport consumption of the filament, which allows the filament to glowbrightly when electricity passes through.

With a single headlamp system, we have a lamp with two filaments: onefor low beam and one for high beam. The low-beam filament is shieldedwith a metal shield, which allows the light to reflect off the silverdish through the glass to the road ahead. The high-beam filament isn'tshielded, which allows light to pass directly to the road ahead, plusadditional multiplied reflection off the silver dish. Twin-setheadlamps, such as those we see on the '69 Mustang, nearly all of theGalaxies and big Mercurys, Fairlanes, Comets, and Cyclones, work usingone headlamp for low beam and another for high beam. The low-beamheadlamp has the shielded filament, just like we see in the low-beamside of a single lamp. The high-beam headlamp has an unshieldedfilament, which comes on when the high-beam switch is depressed.

Because a conventional sealed-beam headlamp is a true vacuum envelope,it works fine as long as that vacuum is maintained. A stray stone or acollision may break the glass, which destroys the vacuum, allowingoxygen in to consume the filament. Poof!

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