FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
Courtesy of Operation CHARM: Car repair manuals for everyone.

Cold Weather Adjustment

^ If the horn (3) fails to sound in cold weather, the current limit may be set too low, even if the horn (3) is still within the amperage limit. Do not make this adjustment unless the horn fails to sound in cold weather. A current increase on a properly functioning horn may result in damage to the horn.
^ Turn the adjusting screw (2) 1/4 turn (90 degrees) counterclockwise in order to increase the current draw until the horn sounds.