What causes B1279 on a Honda?

Faulty dimmer switch Dimmer switch harness is open or shorted Dimmer switch circuit poor electrical connection Faulty multiplex integrated control unit (MICU) Faulty combination switch control unit

How do I fix B1279 on a Honda?

Confirm the code with a scan tool and check the MICU for related faults Inspect the switch connector for corrosion, moisture, and loose pins Test the switch contacts and the signal at the MICU through each position Check the wiring for an open or short before replacing the switch Replace the dimmer switch if it fails testing, then clear codes and retest

B1279 The MICU saw a fault in the dimmer switch circuit

Q: What does B1279 mean on a Honda?

B1279. The MICU saw a fault in the dimmer switch circuit. The instrument panel lights may not dim or brighten with the control. Applies to Honda and Acura models that use this code.

Category: Body
Severity: Body Warning Light
Applies to: Honda and Acura models that use this code

What does B1279 mean on a Honda?

B1279. The MICU saw a fault in the dimmer switch circuit. The instrument panel lights may not dim or brighten with the control. This Honda-enhanced code applies to Honda and Acura models that use this code.

Common causes of B1279

Faulty dimmer switch
Dimmer switch harness is open or shorted
Dimmer switch circuit poor electrical connection
Faulty multiplex integrated control unit (MICU)
Faulty combination switch control unit

How to fix B1279

Confirm the code with a scan tool and check the MICU for related faults
Inspect the switch connector for corrosion, moisture, and loose pins
Test the switch contacts and the signal at the MICU through each position
Check the wiring for an open or short before replacing the switch
Replace the dimmer switch if it fails testing, then clear codes and retest

Sources and review

Last updated 2026-09-29.