Rear Defogger Antenna System

WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

IMPORTANT: The following information lists the most probable cause of the concern to the least probable cause followed by the appropriate test for that condition. If the test leads to the replacement of a component, always inspect for a poor connection before proceeding with the replacement. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

This antenna system uses the existing rear defogger grid as an antenna. Using the defogger as an antenna requires the circuitry in the radio antenna module to decouple the RF from the DC heater current.

Perform the Antenna System Test and test the antenna coax cable prior to performing the following tests.

The radio antenna module is not grounded properly. The module grounding screws should be clean and tight. Measure the resistance from the antenna module base plate to a good ground. Resistance should be 0.2 ohms or less. Find and correct the condition if the resistance is out of specification.
The antenna relay coil supply voltage circuit to the radio antenna module is open or shorted to ground. Test the antenna relay coil supply voltage circuit for an open or short to ground. Refer to Circuit Testing andWiring Repairs .
Defective radio antenna module-Replace the radio antenna module.
No antenna relay coil supply voltage output from the radio-Disconnect the radio antenna module connector. Turn ON the radio and measure the voltage from the antenna relay coil supply voltage circuit of the radio to a good ground. Voltage measured should be near 12 volts. If no voltage is measured, replace the radio. Refer to Radio Replacement for service procedure.
If noise is present when the rear defogger is ON, inspect the rear defogger grid for breaks. Repair as necessary.
After finding and correcting the condition, operate the system in order to verify the repair.