Circuit/System Testing

Rear Glass Antenna Testing

1. Inspect the antenna on the rear glass. Verify all branches of the antenna are intact, with no scratches or other damage.
   • If damage is found, repair or replace as necessary.
2. Verify the connector at the back glass is properly secured and free of any damage.
   • If damage is found, repair or replace as necessary.
3. Inspect the radio antenna module grounding surfaces and the mounting hardware for any corrosion that may cause a poor ground.
   • If corrosion is noted, clean the grounding surfaces or hardware.
4. Ignition OFF, disconnect the harness connector at the radio antenna module.
5. Ignition ON, radio ON, test for B+ between the signal circuit terminal 1 and ground.
   • If less than the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
6. Disconnect the antenna coax from the radio and the radio antenna module.
7. Test for infinite resistance between the antenna coax center terminal and ground.
   • If less than the specified value, replace the antenna coax.
8. Test for infinite resistance between the coax center terminal and the outer shield.
   • If less than the specified value, replace the antenna coax.
9. Test for less than 5 Ω on the antenna coax center terminal from end to end.
   • If greater than the specified value, replace the antenna coax.
10. Test for less than 5 Ω on the antenna coax outer shield from end to end.
    • If greater than the specified value, replace the antenna coax.
11. If all circuits test normal, replace the antenna module. Reconnect the antenna coax.
12. Ignition ON, radio ON, verify radio reception has improved.
    • If reception is still poor, replace the radio.

Fixed Mast Antenna Testing

1. Ignition OFF, disconnect the radio antenna coax cable from the radio and the radio antenna.
2. Test for infinite resistance between the antenna coax center terminal and ground.
   • If less than the specified value, replace the antenna coax.
3. Test for infinite resistance between the coax center terminal and the outer shield.
   • If less than the specified value, replace the antenna coax.
4. Test for less than 5 Ω on the antenna coax center terminal from end to end.
   • If greater than the specified range, replace the antenna coax.
5. Test for less than 5 Ω on the antenna coax outer shield from end to end.
   • If greater than the specified range, replace the antenna coax.
6. Reconnect the coax to the radio antenna. Test for infinite resistance on the coax at the radio between the center terminal and the outer shield.
   • If less then specified value, replace the antenna.
7. Test for less than 10 Ω on the coax at the radio between the outer shield and ground.
   • If greater than specified value, clean the mounting surface of the antenna ground plane. If no corrosion found, replace the antenna.
8. If all circuits test normal, replace the radio.