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Home >> Hummer >> 2008 >> H3 Alpha >> Repair and Diagnosis >> External Pages >> Different car >> Section 399 (Cellular System, Entertainment System, And Navigation System) >> Diagnostic Information and Procedures >> Navigation System - Poor or Inoperative TV Reception >> Circuit/System Testing
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Circuit/System Testing

WARNING: This page is about a different car, the 2009 Cadillac STS. However, it is still accessible from the selected car via links, so may be relevant.
IMPORTANT: Verify the radio is operating normally before performing this diagnostic. If audio distortion is present, refer to Speaker Malfunction 
  1. Inspect the TV antenna grid for damage and that each of the TV antennas are connected.
    • If damage is found, replace the rear glass.
  2. Ignition OFF, disconnect all TV antenna leads from the rear glass.
  3. Ignition ON, rear defog/defrost ON, test for less than 1 volt on each of the antenna lead connectors on the rear glass.
    • If greater then specified value, replace the rear glass.
  4. Ignition OFF, disconnect the TV antenna leads at the rear glass and the TV antenna amplifier and test each antenna lead for infinite resistance to ground.
    • If less than specified value, replace the appropriate antenna lead.
  5. Disconnect both end of the antenna leads from the rear glass and the antenna amplifier and test for less than 5 ohms between both ends of each antenna lead.
    • If greater than specified value, replace the appropriate antenna lead.
  6. Ignition OFF, disconnect the antenna coaxial cables between the TV antenna amplifier and the TV antenna module.
  7. Test for less than 5 ohms between the coaxial center conductors.
    • If greater than specified value, replace the TV antenna coaxial cable.
  8. Test for less than 5 ohms between the coaxial outer shield conductors.
    • If greater than specified value, replace the TV antenna coaxial cable.
  9. Reconnect all of the coaxial cables at the TV antenna amplifier and the TV antenna module.
  10. Disconnect the TV antenna module harness connector and the TV antenna coax at the radio.
  11. Verify there is less than 5 ohms between terminal 13 on the TV antenna module harness connector and the TV antenna coaxial cable center conductor at the radio.
    • If greater than specified value, replace the TV antenna coaxial cable.
  12. Reconnect the TV antenna module harness connector and the TV antenna coax at the radio.
  13. Disconnect the X2 harness connector from the radio.
  14. Ignition ON, radio ON, tune the TV in to a known good station. Test each of the following circuits test for a varying mV AC voltage reading between the following signal circuit terminals listed below and ground an open, short to ground, or a short to voltage.
    • The audio left circuit terminal 1
    • The audio right circuit terminal 2
    • The audio common circuit terminal 9
    • If the voltage reading is not as specified, test the signal circuit for a short to voltage, short to ground, or an open/high resistance. If the circuit tests normal, replace the TV antenna module.
  15. If all circuits test normal replace the radio.
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