The following table outlines detail MerCruiser Wiring Colors Code. Please note that Color codes listed below DO NOT apply to fuel injection system harnesses.

and Abbreviation Function and Location

Black (BLK)
Brown (BLU)
Orange (ORN)
Lt. blue/White (LT BLU/WHT)
Gray (GRY)
Green/White (GRN/WHT)
Tan (TAN)
Light blue (LIT BLU) 
Pink (PNK) 
Brown/White (BRN/WHT)
Purple/White (PUR/WHT)
Red (RED)
Red/purple (RED/PUR) 
Red/purple (RED/PUR) 
Orange (ORN)
Purple/Yellow (PUR/YEL) 
Purple (PUR)
Yellow/Red (YEL/RED)

All Grounds
Reference Electrode – MerCathode
Anode Electrode-MerCathode
Trim – ”Up” Switch
Tachometer Signal
Trim – ”Down” Switch
Water Temperature Sender to Gauge
Oil Pressure Sender to Gauge
Fuel Gauge Sender to Gauge
Trim Sender to Trim Gauge
Trim – ”Trailer” Switch
Unprotected Wires from Battery
Protected (Fused) Wires from Battery
Protected (+12V) to Trim Panel
Alternator Output
Ballast Bypass
Ignition Switch (+12V)
Starter Switch to Starter Solenoid to Neutral Start Switch

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