B1279 Dimmer Switch Circuit Malfunction

OBD2 Code: B1279

Description: Dimmer Switch Circuit Malfunction

Definition: This code indicates a malfunction in the dimmer switch circuit, which is responsible for controlling the brightness of the vehicle’s dashboard lights. The issue could be due to a faulty dimmer switch, wiring problems, or a failure in the associated control module.

B1279 – Dimmer Switch Circuit Malfunction

Typical Severity: Moderate

Common Causes

B1279 – Dimmer Switch Circuit Malfunction

Common causes:

• Faulty dimmer switch
• Short circuit in the dimmer switch wiring
• Loose or corroded electrical connections related to the dimmer switch
• Faulty body control module (BCM)

Common Misdiagnosis

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OBD2 Code: B1279

Description: Dimmer Switch Circuit Malfunction

Common Misdiagnosis: Replacing the dimmer switch without checking for wiring issues or a faulty connection in the circuit.

Common Diagnostic Steps

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OBD2 Code: B1279

Description: Dimmer Switch Circuit Malfunction

• Inspect the dimmer switch for physical damage or wear.
• Check the wiring and connectors related to the dimmer switch for corrosion, loose connections, or damage.
• Use a multimeter to test the voltage and continuity of the dimmer switch circuit.
• Examine the fuse associated with the dimmer switch circuit and replace if necessary.
• Test the vehicle’s lighting control module for faults that may affect the dimmer switch operation.
• If equipped, use an OBD2 scanner to clear codes and see if they return after performing repairs.