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Home >> GMC >> 2022 >> Terrain SLT, FWD >> Repair and Diagnosis >> Accessories & Equipment >> Gauges & Instrument Panels >> Displays And Gauges >> Diagnostic Information and Procedures >> DTC B12AC >> Component Testing

Component Testing

  1. Ignition OFF/Vehicle OFF, disconnect the harness connector at the S27 Head-Up Display Switch.
  2. Test for 14K - 16K Ω between the signal terminal 4 and the low reference terminal 3.
    • If not between 14K - 16K Ω 

      Replace the S27 Head-Up Display Switch.

    • Go to next step: If between 14K - 16K Ω 
  3. Test for 6K - 8K Ω between the signal terminal 4 and the low reference terminal 3 with the DIM - Switch pressed.
    • If not between 6K - 8K Ω 

      Replace the S27 Head-Up Display switch.

    • Go to next step: If between 6K - 8K Ω 
  4. Test for 3.5K - 4.3K Ω between the signal terminal 4 and the low reference terminal 3 with the DIM + Switch pressed.
    • If not between 3.5K - 4.3K Ω 

      Replace the S27 Head-Up Display switch.

    • Go to next step: If between 3.5K - 4.3K Ω 
  5. Test for 2.2K - 2.6K Ω between the signal terminal 4 and the low reference terminal 3 with the INFO/PAGE Switch pressed.
    • If not between 2.2K - 2.6K Ω 

      Replace the S27 Head-Up Display Switch.

    • Go to next step: If between 2.2K - 2.6K Ω 
  6. Test for 1.3K - 1.6K Ω between the signal terminal 4 and the low reference terminal 3 with the ON/OFF Switch pressed.
    • If not between 1.3K - 1.6K Ω 

      Replace the S27 Head-Up Display Switch.

    • Go to next step: If between 1.3K - 1.6K Ω 
  7. Test for 750 - 910 Ω between the signal terminal 4 and the low reference terminal 3 with the DOWN Switch pressed.
    • If not between 750 - 910 Ω 

      Replace the S27 Head-Up Display Switch.

    • Go to next step: If between 750 - 910 Ω 
  8. Test for 360 - 440 Ω between the signal terminal 4 and the low reference terminal 3 with the UP Switch pressed.
    • If not between 360 - 440 Ω 

      Replace the S27 Head-Up Display Switch.

    • Go to next step: If between 360 - 440 Ω 
  9. All OK.