Poor Reception On Both AM And FM Bands

^ The radio antenna module is not grounded properly. The module grounding screws should be clean and tight. The antenna module ground is either a chassis ground or a ground strap. Measure the resistance from the antenna module base plate to a good ground. Resistance should be 0.20 Ohms or less. Find and correct the condition if the resistance is out of specification.
^ The antenna enable signal is not present at the radio antenna module. This could be caused by an output failure of the radio or an open/shorted antenna enable signal circuit. In order to test the antenna enable signal circuit, the radio must be ON and tuned to the FM band.
Disconnect the radio antenna module. Measure the voltage from the antenna enable signal circuit of the radio antenna module to a good ground. Voltage measured should be near 12 V. If the specified voltage is measured, test the antenna enable signal circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Diagnostic Aids. If no failures were found, replace the radio. Refer to Radio Replacement for service procedure.
^ The FM composite signal circuit to the radio antenna module is open or shorted to ground. Test the FM composite signal circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Diagnostic Aids.
^ The feed coax at the radio antenna module has been inadvertently swapped with the FM impedance matching module crossover coax. Ensure that the feed coax, marked with a yellow band, is in the correct socket on the radio antenna.
^ Improper retention of the antenna cable in the floating retainer. Poor or no connection with the radio will result when the radio is installed if the antenna cable is not properly attached in the floating retainer. Inspect the antenna cable for movement in the floating retainer. Replace the antenna cable if movement is found.
^ Defective radio antenna module. Replace radio antenna module. Refer to Radio Control Module Replacement for service procedure.