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Circuit/System Testing

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  1. Inspect the trailer rear fog lamp bulb for an open or shorted filament.
    • If the bulb is inoperable, replace the bulb.
  2. Park lamp switch OFF, clear the DTC, test the trailer rear fog lamp circuit for a short to voltage, short to ground, an open, or high resistance.
    • If all circuits/connections test normal, replace the XBCM.