HEAD LIGHT MODULATION IN WASHINGTON STATE

The WAC And What You Need To Know

If you ride with a head light modulator, or plan to in the future it's a good idea to carry a copy of the Washington Administrative Code related to the usage of Headlamp Modulators. All too often we hear of riders who have been cited by the State Patrol, only to waste time and tax payers money in court.

Finding a copy of the state code is another story. To get it off the internet it takes a lot of plunking around, and just locating the first part isn't an easy task. As it's public domain, we've made it easy for you. Print it, wrap it up in a plastic bag and carry it under your seat.

By authority of RCW 46.37.005 and 46.37.320, the state commission on equipment hereby adopts the following standards for motorcycle electronic headlamp modulators.

This standard shall apply only to electronic headlamp modulators for use on motorcycles and motor-driven cycles.

(1) "Electronic light modulation" means the periodic change in intensity of light, controlled by an all electric modulating device in the electrical circuit of the lighting system.

(2) "Percent modulation" equals time-weighted power input with modulation to headlamp divided by time weighted power input without modulation to headlamp times one hundred.

(3) "Electronic modulation" means using one hundred percent electronic circuitry instead of mechanical metallic switches.

(1) Electrical. The modulator shall be inserted in the high beam headlight circuit on motorcycles between the high beam hand switch and high beam filament in the lamp.

(2) Physical. The modulator shall be located on a frame bar or other substantial structure number, easily accessible to the operator for quick access to a bypass switch. The device should be air cooled, if necessary.

(3) Safety redundancy. The low beam headlight circuit should be unaltered and used as backup in case of modulator malfunction.

(1) The modulator shall be designed to continuously operate 60 watt headlamps.

(2) The modulator shall have an electrical bypass switch rated at 6 amps, 12.8 volts.

(3) Provisions shall be made to change modulation amplitude:

a. Daytime - modulation depth should be at least 50% but not more than 80%.

b. Nighttime - not more than 20% modulation.

c. At no time while the light modulator is being used should the percent modulation become 100. This condition switches off the light intermittently and leads to premature filament failure.

(4) All interconnecting wire should be No. 16 AWG stranded copper.

(5) The light modulator should be capable of operating over a voltage range of from 8 to 14 volts with no discernible change in its operating characteristics other than in headlamp brightness.

(6) Potentially dangerous voltages, i.e., above 50 volts should not be used in the light modulator.

(7) The modulator should operate within a frequency band of one cycle every two seconds to not more than four times per second.

(8) The units should be sealed to prevent water intrusion.

(9) The modulator should be designed to withstand intense vibration at 130°F.

(10) No changes shall be made to render ineffective Motor Vehicle Safety Standard 108.

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For more information about Head Light Modulators, or to find the one that is right for your bike,CLICK HERE .