Noise Diagnosis

^ The following describes the ways that noise may enter a sound system and general solutions. See Symptom Table for specific symptoms and diagnosis.

NOISE CAN ENTER A RADIO SYSTEM FOUR WAYS:

Frontway

Any noise which can be eliminated by unplugging the Antenna from the back of the Radio

Causes:

- Poor grounding of: the Antenna, the Radio, some electrical component or body parts

- Defective or marginal components: relays, solenoids, switches, electric motors

- Something near the antenna lead-in or corrosion at lead-in connections

Solutions:

- Always verify grounding first: if more than one component interferes, a poor ground probably exists.

- Pinpoint the source: suppress, shield or replace. Re-route noisy wires if necessary.

Sideways

Any noise which gets quieter when slowly removing the Radio from the Instrument Panel

Causes:

- Noisy wiring or hoses behind or on top of the Radio or antenna lead-in

Solutions:

- Suppress or shield the noisy wire or hose, or re-route it. Shield the Radio.

Backway

Any noise that can be heard at minimum volume

Causes:

- Poor grounding of: the Radio, an unsuppressed electrical component, poorly routed wires or defective suppression of an electrical component

Solutions:

- Suppression can be installed at the source (preferable), the Radio, or both.

- Pops are best suppressed using capacitors. Squeals and buzzes are best suppressed using filters.

Harness Related Noises

Causes:

- Pinched wires, broken or shorted audio wires, defective connectors or speakers, defective Delco-GM/Bose amplifier, faulty shield wires, screw through wire harness

Solutions:

- Localize problem to one side. front or back or speaker location.

- Verify speaker/amplifier operation using spare speaker/amplifier.

- Use channel swap harness (1226788) to check wiring.

- Track wiring for defects, breaks or shorts.

Note: Harness related noises have a tendency to be intermittent.