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Home >> Isuzu >> 2007 >> i-290 LS, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 9 (Instrument Panel System Displays And Gauges) >> Diagnostic Information and Procedures >> Outside Air Temperature Display Inaccurate or Inoperative >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2007 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF disconnect the harness connector at the OAT sensor.
  2. Ignition OFF, test for less than 1 ohm of resistance between the ground circuit terminal and ground.
    • If greater than 1 ohm, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the driver information center (DIC) displays approximately -40°F (-40°C).
    • If the DIC does not display approximately -40°C (-40°F), test the OAT sensor signal circuit for a short to ground. If the circuit tests normal, replace the HVAC module.
  4. Ignition ON, perform an outside air temperature Instant Update to by pass filtering by simultaneously pressing the following switches on the HVAC control module:
    • LEFT TEMPERATURE UP
    • PASS ENABLE
    • REAR DEFOG ENABLE
  5. Ignition ON, install a 3-amp fused jumper wire between the signal circuit and the ground circuit of the OAT sensor. Verify the DIC displays approximately 189.5°F (+87.5°C).
    • If the DIC does not display approximately 87.5°C (189.5°F), test the signal circuit of the OAT sensor for a short to voltage or an open/high resistance. If the circuit tests normal, replace the HVAC module.
  6. If all circuits test normal, test or replace the OAT sensor.
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