Standard Boat Wiring Color Codes

These are the most common color codes used in boat wiring.

Black  Grounds, General
Black/Brown  Pump Grounds 
Black/Red  Voltmeter Grounds 
Black/Orange  Isolated Accessory Grounds 
Black/Yellow  Ignition stop 
Black/Green  Water Level Sender Ground 
Black/Blue  Lighting Grounds 
Black/Gray  Nav Light Grounds 
Black/White  Battery Parallel Solenoid 
Brown  Pumps, General, Bilge or Sump (Manually Switched)(Also alternator starter to Ign.) 
Brown/Red  Pumps, Bilge or Sump 
Brown/Orange  Power feed to Auto Bilge Switches, Pumps, Fuel/Oil Tranfer or Priming 
Brown/Yellow  Baitwell or Aerator 
Brown/Green  Fresh Water Pump/Water Maker 
Brown/Blue  Head Pump 
Brown/Violet  Washdown Pump 
Brown/White  Trim pos sender 
Red  Battery Feeds Unprotected 
Red/Violet  Misc. Accy. Main Feed Protected (fused) from batt to trim panel. 
Pink  Fuel Sender 
Orange/Black  Audio System Feed 
Orange/Brown  Electric Head, Sanitation System 
Orange/Red  Wiper Port 
Orange  Accessories common feed, Dist Panel to Acc switch, Anode Electrode, Mercathode 
Orange/Yellow  Diesel Preheat
Orange/Green  Wiper Stbd 
Orange/Blue  Communications Equipment 
Orange/Violet  Navigation Equipment 
Orange/White  Wiper Center 
Yellow/Black  Choke  Neutral saftey trans mounted 
Yellow/Red  Start Solenoid (starting circut), Neutral Safety 
Yellow/Orange  Powered Ventilation, Fans 
Yellow  Bilge Blowers (also alternator DC output) 
Yellow/White  Rudder Angle Sender 
Green/Red  Stop Solenoid/Kill Switch 
Green/Yellow  AC Grounding 
Green  Bonding 
Green/White  Engine Trim in and or tilt down 
Green/Orange  Engine Independent Trim down 
Blue/Black  Cabin Lights 
Blue/Brown  Oil Temp Send 
Blue/Red  Cabin or Cockpit Lights Port 
Blue/Orange  Engine Independent Tilt Up 
Blue/Yellow  Lighting Circuits to Remote Send 
Blue/Green  Cabin or Cockpit Lights Stbd 
Blue  Instrument & General Lighting 
Blue/Violet  Courtesy, Boarding Lighting 
Blue/White  Engine Trim Outand/or Tilt Up 
Light Blue  Oil Pressure 
Violet/Red  Eng. or Generator B+ from Breaker 
Violet/Yellow  I/O Trim Up (ballast bypass) 
Violet/Green  I/O Trim Down 
Violet  12v Ignition Generator or Engine 
Violet/White  Trim "Trailer" switch 
Gray/Black  Mast Light 
Gray/Red  Spotlight Remote 
Gray/Orange  Docking Lights 
Gray/Green  Strobe or Beacon 
Gray/Blue  Spreader/Flood Lights 
Gray/Violet  Windlass/Winch 
Gray  Navigation (running) Lights, Tach. Send 
Gray/White  Anchor Light 
White/Brown  Temp. Alarm or Indicator 
White/Red  Fuel Alarm or Indicator ((Ignition module to Dist.)Mercury Thunderbolt Ignition) 
White/Orange  Fire Alarm or Indicator 
White/Yellow  Air Flow Alarm or Indicator 
White/Green  Water Press/Flow Alarm or Indicator ((Ignition module to Dist.)Mercury Thunderbolt Ignition) 
White/Blue  Oil Press Alarm or Indicator 
White/Violet  Voltage Alarm or Indicator 
White  General Alarm Usage, Yamaha Kill Switch 
Tan  Water Temp sender 
Tan/Blue  Warning system sense wire (Audio warning)