Corrective Action

Use the correct tools for diagnosis and repairs. Be sure to follow the ESD guidelines.

The following noise suppression devices are available:
^ 220 mF (50 V) capacitor GM P/N 1227895
^ 0.47 mF capacitor GM P/N 1227894
^ Fuse block capacitor GM P/N 469328
^ Feed through capacitor GM P/N 477371
^ Filter package GM P/N 1224205
^ Turn signal suppression GM P/N 3861565
^ Fuel pump suppressor GM P/N 25027405
^ 53.3 cm (21 in) braided ground strap GM P/N 8910791
^ 48.3 cm (19 in) braided ground strap GM P/N 6286800
^ 26.7 cm (10.5 in) braided ground strap GM P/N 6287160
^ 21.6 cm (8.5 in) braided ground strap GM P/N 12091511

Use the Test Tape/CD Diagnosis Kit GM PIN J 39916-A to assist in optimizing the diagnosis.

If the condition requires you to send the radio to the service center, describe the symptoms accurately on the warranty form. Send a copy of the Service Writer Check List along with the warranty form.

Take the following precautions in order to prevent damage to CDs and cassettes:
^ Do not leave CDs or cassettes in the car. Extreme heat may cause permanent damage to CDs and cassettes.
^ Store cassettes in their cases. The vibration in the vehicle may cause the tape to unwind inside of the cartridge.

Complete the following steps before you remove the speakers:
^ Inspect all of the connectors and wiring to the speakers.
^ Examine the connectors for bent or loose pins.

If you test an antenna, ground the antenna base to the vehicle body. Do not hold the mast.

IMPORTANT: Inspect the antenna coax connectors for the following conditions:
^ Corrosion
^ Poor connections
^ Crimps
^ Shield the antenna coax interconnections with aluminum or nickel tape.
^ Inspect the following grounds:
^ The radio grounds
^ The antenna grounds
^ All of the remaining grounds in the vehicle.
Coated bolts and screws may be poor grounds. Use a braided ground strap when you apply a ground.

Keep the ground strap as short as possible. Use aluminum toil tape or nickel tape in order to shield against magnetically induced interference when shielding the following components:
^ The dash
^ The wires
^ The hoses

Most hoses are conductive. Hoses that are not conductive have a white stripe.

Vary the following ground techniques for optimum grounding results:
^ Add a ground at both ends of the tape.
^ Add a ground to just one end of the tape.
^ Do not add ground to the tape.

Complete the following steps when shielding a harness with tape:
^ Attach a ground strap to the end of the tape.
^ Wrap the strap 3600 around the tape.
^ Secure the other end of the strap to a known good chassis ground.

If possible, correct any interference at the source of the interference.

Apply suppression carefully. The following wires can be suppressed:
^ The battery wires
^ The ignition wires

Signal wires cannot be suppressed. The following wires are examples of signal wires that cannot be suppressed:
^ The sensor outputs
^ The clock
^ The communication circuits

After you apply suppression, inspect all of the vehicle systems for correct operation.

Interference is usually eliminated with the following procedures:
^ Shielding
^ Grounding
^ Suppressing

Use capacitors in order to correct the following conditions:
^ Switch pops
^ Low frequency noise

Use filters in order to correct the following conditions:
^ High frequency whines
^ Static

Whenever possible, make a test harness that includes filters and capacitors. Always verify that a repair is effective and that the systems operate correctly before you permanently install a fix.

Use one of the following capacitor applications for an audible pop that is induced by a switching operation:
^ Add a capacitor across the contacts of the switch.
^ Add a capacitor from the hot side of the switch to the ground.
^ Add a capacitor to each side of the switch to the ground.

Complete the following inspections if the condition is present only when the ignition is in the RUN position and the engine is running:
^ Inspect the integrity of the ignition system. Refer to Computers and Control Systems. Computers and Control Systems
^ Inspect the integrity of the engine compartment grounds.
^ Inspect for the following conditions that may cause noise or poor reception:
- Malfunctioning relays
- Malfunctioning solenoids
- Malfunctioning system components
^ Inspect the integrity of the ground for the component that is causing the complaint.

Perform the Antenna System test for noise or poor reception. Repair the system as needed. Refer to Antenna Extension Cable Replacement. Service and Repair