Reading Wire Colors and Connectors

Every wire on a schematic has a color code. These colors match the actual wires on the vehicle. This is how you find the exact wire you need to test among the dozens or hundreds of wires in a harness.

BLK = black. WHT = white. RED = red. BLU or BL = blue. GRN or GN = green. YEL or YL = yellow. ORN or ORG = orange. PNK or PK = pink. BRN or BN = brown. GRY or GY = gray. PUR or PPL = purple. LT = light. DK = dark. A wire labeled LT GRN means light green. DK BLU means dark blue. RED/WHT means a red wire with a white stripe — also written as RD/WH. The first color is the base color of the wire. The second color after the slash is the stripe or tracer color. This two-color system allows manufacturers to have hundreds of uniquely identifiable wires in the vehicle.

Connectors on the schematic are labeled with an identifier — like C145 or X215 or a manufacturer-specific code. This number corresponds to a physical connector on the vehicle. The component locator section of the service information shows you where that connector is physically located. Each pin in the connector is numbered. The schematic shows which wire connects to which pin. This lets you back-probe or unplug a specific connector and test a specific pin to check voltage, ground, or continuity on that exact wire.

A splice point is shown as a dot where two or more wires connect together — like a T or Y intersection. This is where multiple circuits share a common connection point. A bad splice affects every circuit that meets at that point. If you see three circuits that all stopped working and the schematic shows they all pass through the same splice — that splice is your prime suspect. Splice points are labeled with an identifier that helps you find the physical location on the vehicle.