Automotive Service Excellence (ASE) A6 Electrical/Electronic SystemsGeneral Electrical/Electronic System DiagnosisEasy

A technician is using service information to troubleshoot an intermittent fault with a vehicle's anti-lock braking system (ABS). The wiring diagram shows a wire labeled 'C140-12A-GN/RD'. What does the 'GN/RD' designation most likely represent?

  1. AThe wire's primary and secondary colors.
  2. BThe circuit number and gauge.
  3. CThe connector pin number.
  4. DThe wire's insulation type.
Show answer & explanation

Correct answer: A. The wire's primary and secondary colors.

In automotive wiring diagrams, two-letter abbreviations separated by a slash (e.g., GN/RD) typically denote the wire's primary color (e.g., Green) and a stripe or secondary color (e.g., Red). This helps technicians visually identify specific wires within a harness.

Why the other options are wrong

  • B. Circuit number and gauge are usually indicated by numbers or codes, not color abbreviations.
  • C. Connector pin numbers are usually part of the connector identifier (e.g., C140-12), not the color code.
  • D. Insulation type is generally not specified directly in the wire label on a diagram.

Wiring Diagram Color Codes

Standardized two-letter abbreviations used in automotive wiring diagrams to represent wire insulation colors for identification.

  • Primary color is listed first (e.g., GN for Green).
  • Secondary color (stripe) is listed after the slash (e.g., RD for Red).
  • Helps technicians locate specific wires in a harness.

Memory trick: GN/RD: Green for Main, Red for Stripe, A Wire's True Colors.

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