Initial Inspection and Diagnostic Overview

Note: Perform before beginning System Diagnosis

Radio Inoperative:
1. For checking a speaker, use a "C" or "D" cell Battery and momentarily connect and disconnect it across the circuits to that speaker while listening for a slight popping sound or watching for the cone of the speaker to move in and out. If either happens, the speaker and circuitry are usually OK.
2. Check Fuse 8. If open, check for a short to ground through CKT 40.
3. Check Fuse 17. If open, check for a short to ground through CKT 43.
4. Make sure ground G200 is clean and tight.

Radio Noise:

Note: A noise "sniffer" may be used to aid in troubleshooting Radio noise. For definitions of the different types of Radio noise, refer to "Noise Entry."

1. Test the Radio outside with the hood down.
2. Ignition noise on FM indicates a possible defective High Energy Ignition (HEI) System.
3. If a test antenna is used, ground the base of the antenna to the vehicle body.
4. When shielding components, use aluminum foil tape (nickel tape works best) and ground both ends of the shield.

General:
^ Check for a broken (or partially broken) wire inside of the insulation which could cause system failure but prove "GOOD" in a continuity/voltage check. Use Test Light J 34142 whenever possible. Test lights require more current than a high impedance DVM and are more useful for detecting abnormally high resistive circuits. Some test lights have high impedances and will not be as useful in detecting resistive circuits.

^ Check for proper installation of aftermarket electronic equipment which may affect the integrity of other systems