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Home >> Pontiac >> 2009 >> Torrent Base, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 74 (Lighting Systems) >> Diagnostic Information and Procedures >> Interior Backlighting Malfunction >> Circuit/System Testing >> Dimmer Switch Circuit Test
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Dimmer Switch Circuit Test

WARNING: This page is about a different car, the 2008 Pontiac Torrent and 2008 Chevrolet Equinox. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connector at the dimmer switch.
  2. Ignition OFF, verify that a test lamp illuminates between the ground circuit terminal C and B+.
    • If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool BCM Dimming Control Signal parameter is less than 0.1 volts.
    • If greater than the specified range, test the signal circuit terminal B for a short to voltage. If the circuit tests normal, replace the BCM.
  4. Ignition ON, test for B+ between the I/P dimming voltage reference circuit terminal D and ground.
    • If less than the specified value, test the voltage reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. Install a 3A fused jumper wire between the signal circuit terminal B and the voltage reference circuit terminal D. Verify the scan tool BCM Dimming Control Signal parameter is greater than 2.6 volts.
    • If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  6. If all circuits test normal, test or replace the dimmer switch.
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