Circuit/System Testing

WARNING: This page is about a different car, the 2008 Isuzu Ascender, 2008 GMC Envoy, and 2008 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.

Antenna Coaxial Cable Testing

The antenna coax is made up of two parts; a coax between the radio and the radio antenna module, and a coax between the radio antenna module and the antenna, which is part of the vehicle rear glass. Disconnect both coax from the radio, radio antenna module, and rear glass.
- If greater than the specified range, replace the antenna coax.
Test for infinite resistance between the antenna coax center terminal and ground.
- If less than the specified value, replace the antenna coax.
Test for less than 5 ohms on the antenna coax center terminal from end to end.
- If greater than the specified range, replace the antenna coax.
Test for less than 5 ohms on the antenna coax outer shield from end to end.
- If greater than the specified range, replace the antenna coax.
Test for infinite resistance between the coax center terminal and the outer shield.
- If less than the specified value, replace the antenna coax.

Radio Antenna Module Test

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.
Ignition OFF, disconnect the harness connector at the radio antenna module.
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.
If all circuits test normal, test or replace the radio antenna module.