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Home >> Cadillac >> 2013 >> Escalade ESV Base, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1128 (Keyless Entry System & Remote Functions) >> Diagnostic Information and Procedures >> DTC B3120 >> Circuit/System Testing
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Circuit/System Testing

WARNING: This page is about a different car, the 2008 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connector at the RF door handle antenna.
  2. Ignition ON, verify a test lamp does not illuminate between the signal circuit terminal A and ground.
    • If the test lamp illuminates, test the signal circuit for a short to voltage. If the circuit tests normal, replace the RCDLR.
  3. Install a DMM between the signal circuit terminal A and the low reference circuit terminal B. Set the DMM to capture AC voltage using the MIN MAX function.
  4. Pull the RF door handle. Verify the DMM captured an AC voltage signal.
    • If an AC voltage was not captured, test the signal circuit and the low reference circuit for a short to ground or an open/high resistance. If the circuits test normal, replace the RCDLR.
  5. If all circuits test normal, test or replace the RF door handle assembly.