The Ford Aerostar is not well known for its headlight output. To many, the beam pattern seems weak and the light output is fairly low. However, the headlights do have potential. This article pertains mostly to the '92 and newer models, the ones with the plastic headlights. However, many of the electrical principles apply to all years.
Lens Clarity
Obviously, if your lenses are clear, you will put out more light. The lenses tend to yellow and become opaque over time. The causes of this are debatable. There are headlight restoration kits you can buy that are amazing. They can get the lenses to an almost new clarity. These kits can be purchased from most auto parts stores. There are some other polishing products that work fairly well too, especially if used in conjunction with the restoration kits. I use Flitz myself. There are other products that should give good results as well.
Then begs the question, how do you get the lenses to stay clear? A solution that I have encountered that seems to work is U-Pol Clear #1 UV Resistant Clear Coat (Aerosol Can) . After cleaning and polishing the lenses, go over it again with the finest wet sandpaper, and you can treat the lenses with this clear coating. Do not clean the lenses with a wax polish like Flitz prior to using a clear coat. You should also clean the lenses with acetone to ensure that no oily film is left on the surface, otherwise the coat can crack, bubble, or peel. Take care not to get any acetone on the paint.
Aiming
No headlight can work its best if it is not aimed correctly. None of the Aerostars I have seen had correctly aimed headlights. I don't know if someone has fooled with the adjustments or if they come from the factory like that, but they seem to be aimed way to low, creating a bright zone about 25-50 feet in front of the vehicle, with little light beyond or outside this zone.
Automotive headlights are much more complex than a floodlight. There are designed to catch the light coming off the filament, and aim it down the road in a specific beam pattern. Most of the light is supposed to go straight down the road, and the rest of the light is cast down onto the road surface, and a little bit is cast up and to the right to illuminate signs and road markers. The headlight has what is called a cutoff, which limits the light that might otherwise be cast into the mirrors and eyes of drivers in front of you and also to stop light from glaring into oncoming traffic.
There is excellent reading on the Daniel Stern website, and since they have illustrations and everything, here is what you need to know about aiming the headlights. Daniel Stern Lighting Consultancy and Supply
To adjust the Aerostar headlights, you will need a set of Torx head wrenches, but otherwise, you only need common tools.
Upgrade Bulbs
There is a lot of hype about which bulbs are the best. High end bulbs like Silverstars and Nighthawks claim a brighter and whiter light versus regular bulbs, and there is always the HID crowd. So what is the best type of bulb to use on our beloved Aerostars? The bulb that I use is called the Sylvania Xtravision. It is a brighter version of an otherwise standard halogen. Why did I choose this over the Silverstar? Because the Silverstars create the illusion of being brighter. The Silverstar uses a coated lenses to alter the color of the light output. It doesn't make the light bluer, rather is removes some of the other light colors. This creates the illusion that the light is whiter, and therefore brighter. However, the reality is that the Xtravision is brighter than a Silverstar by about 30%. The Xtravision produces a whitish yellow light, which is a safer night color, provides excellent all around visibility, and does not impair your night vision. It reduces glare, and provides better illumination in adverse weather. It does not attempt to fool the perception by altering the light color, but rather works by actually increasing total light output.
HIDs are another story. HID headlights produce light by creating a plasma arc. This produces an intensely bright light. These lights are much brighter than most halogens, and also consume less power. So they seem like a great upgrade option right? Wrong. HIDs have a much different light source versus a halogen. The halogen reflector is aimed at certain parts of the filament to capture the maximum amount of light and aim it down the road correctly. So what would happen if you change the light source? Halogens are the brightest in the center of the filament, so the stock reflector is aimed at this point, and then has some areas aimed at the less bright regions to fill in the foreground. HIDs in contrast are brightest at the ends of the arc, basically the opposite of a halogen filament. When an HID is put into a halogen reflector, the light is out of focus, and gets scattered. This is similar to the beam adjustment on a flash light, if you change the adjustment, the beam scatters all over. This scattering makes the area surrounding the vehicle much brighter, and increases the overall perception of illumination. However, there is actually less light going where it needs to go. Remember that most of the light is supposed to be cast down the road to let you see where you are going. It is not supposed to be cast in the foreground. The only way to make an HID safe is to use a projector designed for HID bulbs. This at least puts the light where it belongs to improve real visibility and and to reduce glare. However, this is still not legal by DOT regulations. After all this, you can get performance that is safe and legal and much brighter than stock with halogen bulbs. More reading on HID conversions can be found at Daniel Stern Lighting Consultancy and Supply
Upgrade the Wiring
Many of you will be familiar wit this scenario. You are driving along at night, and all the sudden the headlights flicker or go out completely. After a little while they may come back on. You pull off the dash and look at the headlight switch only to find that not only is it bad, but the plastic plug has actually melted? What caused this failure?
The stock wiring is very poor, and is designed to be inexpensive to manufacturer. The headlight switch is not really designed to handle the load that is placed upon it. It has excessive resistance, and the current carrying capacity is low. This dramatically limits the brightness of the headlights. If you put an upgraded bulb, little or no benefit will be noticed unless somehow we can deliver more power to the headlights themselves. So obviously, we need a solution to this problem.
The solution comes in the form of using a good relay and wire harness to carry the electrical load. These harnesses come ready made, or you can build your own. I prefer the ready made systems because they are easy to install and do not require splicing. They are also inexpensive enough. Basically, these harnesses use the stock wiring to trigger the relays, which draw power from the battery directly. The relays can carry more current and have less resistance than the stock headlight switch. This in turn means the bulbs are brighter and whiter, plus it also prevents your headlight switch from melting and increases the life of both the headlight switch and the multifunction switch. The increase current flow means that you can get the most light from your stock bulbs, and also opens up the options for upgrade bulbs. The increase in output can be between 25% — 50%. This is still well within legal limits. In fact, the bulbs are rated and tested and meet DOT regulations at their full output. So this is an upgrade you can do that is fully legal and delivers real results, unlike HID conversions.
This article is intended to educate you about the best options you have for getting the most out of your Aerostar and to maximize the safety and visibility. I am attempting to be as factual as possible, and to help you get past marketing hype and perceptions. Please sticky this.
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