Corrective Action

- Inspect the ground integrity of the component or system causing the noise.
- Malfunctioning and marginal components such as relays and solenoids may cause noise and/or poor reception.
- Always use a braided ground strap when applying additional grounds and keep the ground strap as short as possible.
- If the noise source is found to be coming from the vehicle harness:
- Route the antenna cable separately from the wire harness that is emitting the noise.
- Use aluminum or nickel tape in order to shield the antenna cable. Try variations of the following repairs:
- Try adding only aluminum or nickel tape before adding a ground strap to the tape.
- Wrap a ground strap 360 degrees around the tape, securing the other end of the strap to chassis ground.

IMPORTANT: When installing suppression devices, signal wires such as sensor and communication circuits should not be suppressed. Battery and ignition voltage circuits are the best choices for suppressing.

- Capacitors work best on switch pops and low frequency noise.
- Filters work best on high frequency whines and static.
- After adding any suppression device, inspect all of the vehicle systems (including those not related to the audio system) for proper operation and function.
- Whenever possible, make a test harness that includes filters or capacitors. Always inspect the effectiveness and operation before permanent installation.
- If an audible pop is caused due to operating a switch, perform the following repairs as necessary:
- Add a capacitor across the contacts of the switch.
- Add a capacitor from the battery positive voltage (B+) side of the switch to chassis ground.
- Add a capacitor from the ground side of the switch to chassis ground.
- Use the following available noise suppression devices:
- 220 microfarad (50V) capacitor GM P/N 1227895 - Works well for ignition system related noise.
- 0.47 microfarad capacitor GM P/N 1227894 - Works well for switches and relays.
- Feed through capacitor GM P/N 477371 - Works well for high current situations.
- Filter package GM P/N 1224205 - Works well for low current situations.
- Fuel pump suppressor GM P/N 25027405
- 53.34 cm (21 in) braided ground strap GM P/N 8910791
- 48.26 cm (19 in) braided ground strap GM P/N 6286800
- 26.67 cm (10.5 in) braided ground strap GM P/N 6287160
- 21.59 cm (8.5 in) braided ground strap GM P/N 12091511