Reception

1. Test the radio with the vehicle outside and the hood down.

Check the radio reception in an area away from tall buildings, metal structures, power lines, fluorescent lighting, and power tools.

2. Ignition noise on FM indicates a possible defective Electronic Ignition (EI) System. Refer to Secondary Ignition Noise CELL LINK.
3. Check for proper installation of aftermarket electronic equipment which may affect the integrity of other systems.
4. Check antenna coax connectors for corrosion or bad connections.
5. If a test antenna is used, ground base of the antenna to vehicle body.
6. Coated screws or bolts can act as poor grounds. Do not use threadlocker, or equivalent material, on bolts because it will insulate the ground path.

Wiring and Connections

1. Before removing a speaker, check all accessible wiring and connectors to that speaker.
2. Check for a broken (or partially broken) wire inside of the insulation which could cause system malfunction, but would still 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).

1. Determine the type of audio complaint.
2. Make sure that the customer does not have an aftermarket mobile electronic component, such as a cellular telephone, that has been removed before the vehicle was left for service. This is extremely important, because that component may be emitting the frequency(s) that is (are) causing the complaint.
3. OnStar equipment directly affects the audio system. It is designed to use the vehicle speakers for incoming communications. The audio system, OnStar system, or both, may be contributing to the audio complaint. Refer to the information in this section, and the OnStar system in this service manual.
4. Try to duplicate condition -- listen to AM or FM, start vehicle, put in a good CD or cassette, test switches, etc.

•	Refer to Symptoms - Entertainment for the appropriate diagnostic procedure(s) for hardware related failures or performance complaints.

•	Refer to System Performance Check - Noise or Poor Reception for the appropriate diagnostic procedure(s) for noise or reception complaints.