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post #1 of (permalink) Old 03-08-2012, 03:08 PM Thread Starter
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Putting OEM fog lights to good use in clear weather

I've read the fog light threads here and elsewhere until my eyes turned yellow, but haven't seen this side of the discussion: How can we put those OEM fog lights to good use if we don't have fog or snowstorms to worry about? We know the usual arguments against that:
• For show, they look juvenile.
• For seeing emerging deer sooner, they might help, but not above 20-25 mph.
• They look bright, and their range is severely limited, because they shine primarily on the pavement right in front of our noses.
• Installing brighter bulbs changes none of those all by itself.
• Only driving lights will reach waaayyyyy out there beyond our high beams, and only in a narrow beam (if legal).
• Aftermarket HID conversions are illegal in many states and turn most fog lights into obnoxious, glaring light bombs.

So if we don't need classic fog lights for heavy snow or fog and want to improve our view, in traffic where high beams and driving lights are not practical, beyond just swapping for more powerful bulbs, without bolting too much crap on our bumpers, without attracting cops or paying fines, without blinding others, making max use of existing or stealthy replacement hardware, ... what to do ... what to do?

Replacing the OEM fogs with little bitty round lights -- e.g., better fogs, driving lights, low projector beams -- presents a whole list of problems, from fitment to lighting patterns. Anyone who wants to fabricate a whole new mounting system for that quest needs a hobby ... that, or dweebing with his car IS his hobby.

KISS; aim your existing OEM fog lights higher. HIGHER. MUCH higher! Oops ... that's too much; don't want to irritate everyone, or even just one policeman. Once we point them higher than normal so they aren't glaring off the pavement near our front bumper, their sharp top cutoff and extra beam width let us throw a lot of extra light onto the shoulders of two-lane rural highways and far enough ahead to do some good at highway speeds, and gives our low beams a boost down the road ahead.

"But how?", you ask. "Two ways", I answer.
1. Use the adjustment screw.
2. If that's not enough, tilt them in their mounts or tilt the mounts.
Mechanical details will follow, but first let's understand our objective: it is to raise the projected beam so it's just a little below horizontal. That way it cannot blind oncoming drivers on level roads, and we can't control hilly roads anyway.

We could use Stern's excellent beam aiming geometry tutorial at
Daniel Stern Lighting Consultancy and Supply , or we can use a yardstick, a wall, some masking tape, and some flat ground, plus subsequent fine tuning based on road testing. I favor the latter. Without getting mechanical yet, here's the general approach.

Park on reallyreally flat ground 20, 40, 50 -- whatever -- feet from some vertical target object such as a wall, a tree, another car, a big cardboard box in front of your vehicle. Measure the height of the center of your fog light lens above the ground. Mine's about 17" on my 4th Gen Outback. Place a piece of masking tape horizontally on your target at that height in front of the fog light you're re-aiming. Block your headlight beam with something so your fog light beam upper edge is distinct, and turn on the fogs. Then re-aim your fog light higher ... higher ... higher until its beam's sharp top edge is at, maybe up to a cm above, the masking tape mark. Repeat with the other fog light, then hit the road and make two tests:
1. Make sure your fog light beam's top edge is at or below your properly aimed OEM low beam's top edge at all distances. (That relationship will change with distance because the low and fog lamps are at different heights. I.e., the fog light beam will climb higher at greater distances if it is above horizontal.)
2. Pay attention to oncoming drivers. I don't mind one car out of a hundred flashing me, but 5% tells me they're high enough to blind others and attract cops.

OK, some mechanical details. With built-in OEM fogs, we have two adjustment options: the beam height adjustment screw and shimming. The adjustment screw will help but probably will not bring their beam up to horizontal. If that's your case, as it is on my 4th Gen OB, you'll need to find a way to shim the fog light assembly so it's tilted upwards a bit from stock. It takes only a fraction of a millimeter of shimming, so it's pretty simple. Let's dig one level deeper, using my OB for example.

Drop your plastic fender/splash liners to access your fog lights according to your owner’s manual or Googled instructions. With a flat and a Phillips screwdriver and one or two minutes, that fog light is now fully exposed. You’ll see its adjustment screw or thumbwheel. Turning it clockwise (it takes some effort) raises the beam, but not enough to raise it up to the masking tape you put on your cardboard box. You thus need to shim the assembly to tilt/point it upwards a bit.

How much? We’re trying to raise a beam by mere inches at tens of feet by shimming two mounting points two inches apart; our leverage is hundreds to one. We’re talking about the the thinnest washer we can find for a shim. A hundredth of an inch was enough for my vehicle. Piece o’ proverbial cake!

Now let’s dig one level deeper. The fog light canister has four mounting flanges/ears with holes in them. One is mounted via a single mounting bolt, one slips over a plastic locating stud, and two slip into plastic slots. All that becomes obvious as soon as you bend the splash guards down and look at the light canister. Remove the single bolt, wiggle the light assembly out of its “bed”, and get out your advanced shimming tools and materials: A thin washer that fits over that bolt, a file maybe a half-inch wide, and some duct tape. This is serious stuff!

We want to pull the top of the light back a hair. The washer does that for the bolt side, and the file does that for the plastic slot the other top ear fits into. You want to “move” that upper slot back a tiny amount by filing its back edge off a bit and adding a few wraps of duct tape to its front edge. Precision isn’t necessary; that’s what the adjustment screw is for. I also “moved” (filed) the lower mounting slot/surface forward a little bit so the light assembly isn’t stressed (I doubt that matters) when remounted.

HAH! Now my beam is above the masking tape target, as desired of my mechanical work. I can now bring the beam back down to the tape with the adjustment screw. Time for the road test. If that goes well, I’ll upgrade the bulb to a more efficient (i.e., brighter, but with OEM wattage) bulb.

I’ve also drilled a quarter-inch hole in the plastic liner/pan so I can reach the adjustment screw without even touching the vehicle next time.

Stay tuned. Road test coming soon.

I hope this is clear. I’m not going to bother proof-reading it unless somebody says HUH???

Last edited by AnotherMike; 03-08-2012 at 04:14 PM. Reason: eliminate unexplainable sneak links
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