Fog Lighting

Motivation for the project - many miles ridden in soupy, rainy fog on the Skyline Drive and Blue Ridge Parkway. Click on the bike pictures for installation close-ups.

Fog Lights

Hella Optilux 1100s are fog lights, which mean wide dispersion, and projector, which means there's an internal barrier to force a low cutoff pattern. They are metal-encased and a civilized glossy black.

Bought a couple of these from whit7743 on eBay, came with enough wire and connectors to do the job.


Wanted low position on the Concours to prevent reflected glare from fog. Considered fork mounting, but these lights have one side connected to the metal casing and I didn't want to have any lighting current flowing through the steering head bearing. Even with an explicit ground lead, there's still a parallel path up through the bearing. The best place I could find was the bolt for the bracket holding the coolant reservoir. Others have chosen to mount these lights elsewhere on the Concours.


Didn't use the brackets that came with the lights, instead fabricated some from 3" x 3/4" galvanized steel 'corner braces'.
After one cut and one bend, these brackets attach to the light housing tabs from one side only. Enlarged the hole in the light tab to take a 6mm bolt. The final step was to paint the brackets black.
They mount using the 6mm bolt holding the coolant bracket, and protrude out through vents in the fairing. This arrangement allows up/down adjustment of the lights, but unfortunately none from side to side without bending the brackets - they're quite a spread beam anyway.


The colour codes (e.g. R/BL) are the Concours wiring colours, the words (e.g. Green) are the colours of wires I added. Used a SPDT relay to divert the voltage from the Low Beam to the Fog Lights, saves current and there's no reflected glare from the Low Beam. The diode is to protect other electronic components from voltage spikes when the current through the coil is interrupted. Pulled the R/Y leads out of the connector under the left fairing pocket rather than cut the wires.

The Concours 4-Way Flasher has never seen use, and if I need an emergency flasher for something, there's always the regular flasher. When pressed, the 4-Way Flasher Switch shorts the Green, Orange and Gray wires in the handlebar module. The Orange, Green and Gray wires from the 4-Way Switch enter the cable sheath and merge with the like colored wires from the flasher switch. I cut off the 4-Way Switch wires where they merge in the sheath (leaving the flasher wires unchanged), and used the (longer) Green and Gray 4-Way Switch wires to trigger the relay coil. Ground wires for the lights attach to the brackets/frame ground.

The usual drain with Low Beam is 80W with my NAPA 80/100 headlight, so this increases to 110 watts of fog illumination. There's no change in the operation of the High/Low Beam Switch, turning on High Beam still cuts off Low (or Fog).


Even at idle, the extra current draw doesn't noticeably reduce charging voltage from its typical 14 volts.

Tried in daytime fog on a Blue Ridge Parkway (September '08), couldn't really see any difference between fogs and low beam. Maybe better in fog at night, haven't tried that yet.

Decided (Nov. '08) these weren't for me, fog lights are gone, wiring is back to 4-way flashers.