Wiring diagrams /
1978 Harley Sportster XLH Chopper Diagram
Fitment, source notes & wire connections
CHOPPERCACHE / WIRING REFERENCE
Gold = powered · moving dashes = current
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Key switch OFF ACC ON START
Hold START · release to return to ON Headlight
Current flow
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Choppercache original · By Choppercache
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Diagram reference
An interactive wiring diagram for a 1978 Harley-Davidson Sportster XLH chopper.
This diagram shows 14 components and 18 wire connections. The details below describe the saved diagram; they do not confirm compatibility with your machine.
Recorded fitment 1978 XLH
Configuration Chopper
Circuits labeled in the diagram Charging, Main, Grounds, Lighting, Ignition, Starting
Components shown
GEN · Generator A / GEN and F / external regulator
REG · Regulator F / GEN / BAT
BAT · Battery Negative grounded to frame
GND · Ground Battery negative return
KEY · Key Switch Battery / accessory / ignition-on / spring start
DIMMER · Toggle Switch Two-position selector
HEAD · Headlight High / low beam
COIL · Ignition Coil Key-switched primary
DIST · Distributor Points trigger
BRAKE SW · Brake Switch Normally-open brake-light switch
BRAKE · Brake Light Tail / brake lamp
GND · Ground Brake-light chassis return
SR-791783-1 · Starter Relay Battery / start trigger / motor
M-799428-2 · Starter Motor Case-grounded starter; return through the engine mounting.
Source notes
Choppercache original · Choppercache
Built and maintained by Choppercache.
No external source URL is recorded for this diagram.
Choppercache original · Choppercache
Publication note: Built and maintained by Choppercache.
Limitations and checks
Built and maintained by Choppercache. These recorded references do not establish that this circuit has been tested on your motorcycle. Match the installed components, polarity, terminal pinouts, wire sizes, and circuit protection to the relevant service documentation before applying power.
Verify your hardware pinouts, polarity, wire sizes, and component ratings before applying power.
Wire connections (18)
Wire connections recorded in this diagram
From To Gauge Color BAT · B− GND · GND 6 AWG Black / frame ground BAT · B+ KEY · BAT Reference not shown Diagram red / source unlabeled GEN · A / GEN REG · GEN Reference not shown Diagram green / source unlabeled REG · BAT BAT · B+ Reference not shown Diagram green / source unlabeled KEY · ACC DIMMER · IN Reference not shown Diagram yellow / source unlabeled DIMMER · HIGH HEAD · HIGH Reference not shown Diagram yellow / source unlabeled DIMMER · LOW HEAD · LOW Reference not shown Diagram blue / source unlabeled KEY · ON COIL · KEY Reference not shown Diagram brown / source unlabeled COIL · POINTS DIST · POINTS Reference not shown Diagram brown / source unlabeled KEY · ACC BRAKE SW · IN Reference not shown Reference not labeled BRAKE SW · OUT BRAKE · BRAKE Reference not shown Diagram red / source unlabeled BRAKE · GND GND · GND Reference not shown Black / frame ground KEY · ACC BRAKE · TAIL Reference not shown Diagram yellow / source unlabeled SR-791783-1 · 30 BAT BAT · B+ 6 AWG Red SR-791783-1 · 87 MOTOR M-799428-2 · MOTOR 6 AWG Red SR-791783-1 · 85 GND GND · GND 8 AWG Black KEY · START SR-791783-1 · 86 START Reference not shown Blue GEN · F REG · F Not specified Unknown / verify