Identifying Concerns

^ If the left speaker or the right speaker operates normally except with the remote cassette (optional) in the playback mode, repair the open in CKT 1406 (left) or CKT 1407 (right) between the cassette player and the radio.
^ If the radio clock memory is inoperative, inspect for an open in CKT 1740 between the right side IP wiring harness junction block and the radio. If CKT 1740 is OK, service the radio.
^ Repair the open in CKT 835 between the cassette player and the radio if the following conditions exist:
- The remote cassette player (optional) is inoperative.
- The cassette ejects only with the ignition switch in the OFF position.
^ Acquire any available technical service bulletins. Inquire the dealer communication system for any applicable Preliminary Information (P/I) for customer concerns.
^ If the radio display does not dim with the headlamp switch in the PARK or the HEAD position, inspect CKT 9 for an open. If CKT 9 is OK, service the radio.
^ If the radio display is lit and the backlit switches are not lit, inspect CKT 8 for an open. If CKT 8 is OK, service the radio.
^ For reception concerns, determine if the station is obtainable in the customer's listening area.
^ In order to test for audio reception/noise, position the vehicle outside the building with the hood closed.
^ Duplicate the customer's complaint before attempting to diagnose the system.
1. Ask the customer to demonstrate the condition.
2. Test drive the vehicle with the customer.
3. Test drive a similar model vehicle with a similar audio system.
4. Compare the sound quality in the two vehicles in order to determine if the condition is abnormal.
^ Before diagnosing the system, identify the following items:
^ The components
^ The component features
^ The customer's complaint
^ If any aftermarket equipment was installed on the vehicle, perform the following procedure:
1. Disconnect the aftermarket equipment.
2. Determine if the customer's complaint still exists.
3. Follow GM guidelines for installation of aftermarket components.
^ Perform the following steps in order to identify a noisy component:
1. Identify the ignition key switch position in which the noise appears, including the following positions:
^ Key ON with the engine not running
^ Key ON with the engine running
2. Remove the fuses one at a time until the complaint condition is eliminated.
3. Mark the complaint fuse(s). Reinstall all of the fuses and the circuit breakers.
4. Identify all the systems and components powered by the complaint fuse(s). Refer to Power Distribution Schematics in Wiring Systems. Electrical Diagrams
5. Disconnect the components powered by the complaint fuse(s) one at a time until the complaint condition is eliminated and the noisy component is identified.
6. Inspect the ground integrity of the complaint-causing component.
^ Consider the following points when diagnosing noise in the system:
^ An interference condition is NOT necessarily an audible noise.
^ Most noises are found on weak stations near the low end of the band. These noises are part of a normal condition.
^ An ignition noise on the FM band may indicate a possible defective ignition system.
^ The following items may induce noise or poor reception:
- Malfunctioning and marginal components
- Malfunctioning and marginal relays
- Malfunctioning and marginal solenoids
^ Inspect for a broken (or partially broken) wire inside the insulation. A broken wire may cause a system malfunction but prove GOOD in a continuity/voltage inspection with the system disconnected. The circuits may be intermittent when loaded. Monitor the circuits for a voltage drop with the system operational (under load).