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Motorcycle turn signal control circuit — Harley-Davidson patent US4972174A (1990)

PatentUS4972174A
TypeUtility patent
Filed1989-07-21
Granted1990-11-20
InventorLance C. Onan
SystemLighting

“A turn signal control circuit has a power source, left and right turn signal inputs, a speed detection input and circuitry for conditioning the power source voltage and current as well as the input signals for proper operation. When a turn signal switch provides an input signal to a logic…”

Full patent textDownload PDFShop lighting parts

Drawings (2 sheets)

Motorcycle turn signal control circuit — sheet 1Motorcycle turn signal control circuit — sheet 2

Parts for this system

33-0472
Bates Rubber Boot for H-4 Headlamp Assembly
$6.32
37-1186
Turn Signal Low Head Socket Screw 5/16"-24
$7.02
37-1187
Turn Signal 1/4" Chrome Spacer
$7.02
31-0255
Turn Signal Mounting Clamp Screw Kit
$8.48

Check fitment first — add your bike and we flag what fits.

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Drawing from the US patent record (via Google Patents). A patent shows the invention as filed, not necessarily the production part on your motorcycle — confirm fitment for your model and year. Independent aftermarket retailer, not affiliated with Harley-Davidson, Inc.