Troubleshooting Hints

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 10 if open, check for a short to ground through CKT 640.
3. Check Fuse 38. If open, check for a short to ground through CKT 43.
4. Make sure ground G201 is clean and tight.

Radio Noise:
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) Noise Diagnosis - Noise Entry
1. Test the Radio outside with the hood down.
2. Ignition noise on FM indicates a possible defective Electronic Ignition (EL) System. Refer to Powertrain Management. Powertrain Management
3. Check antenna coax connectors for corrosion or had connections.
4. If a test antenna is used, ground the base of the antenna to the vehicle body.
5. When shielding components, use aluminum foil tape (nickel tape works best for magnetic interference) and ground one end of the shield.
6. Most noise can be found on weak AM Stations near low end of Radio band.
7. Coated screws or bolts can act as poor grounds.
8. Most hoses are conductive unless they have a white stripe.
9. Before removing a speaker, check all accessible wiring and connectors to that speaker.

General:
^ Check for a broken (or partially broken) wire inside of the insulation which could cause system malfunction but prove "GOOD" in a continuity/voltage check with a system disconnected. These circuits may be intermittent or resistive when loaded, and if possible, should be checked by monitoring for a voltage drop with the system operational (under load).
^ Check for proper installation of aftermarket electronic equipment which may affect the integrity of other systems (refer General Troubleshooting Procedures). Diagnostic Aids
^ Refer to System Diagnosis. Initial System Diagnosis