- Verify the customer complaint.
- Refer to the Delco Sound Service Guide (DE SSG) and the Dealer
Service Manuals.
- Fill out the Service Writer Form provided in the DE SSG.
- Follow the radio service procedures.
- Have all of the pertinent information available before placing
a call to technical assistance.
- Consult the DE SSG for a more complete diagnostic overview.
Identifying Concerns
| • | Check for technical service bulletins. Check the Dealer Communication
System for any applicable preliminary information (P/I) for customer concerns. |
| • | Check for stored diagnostic trouble codes. Refer to Engine Controls. |
| • | For reception concerns, determine if the station is obtainable
in the customer's listening area. |
| • | For an FM reception concern, refer to the FM reception section
in the DE SSG. |
| • | For an AM reception concern, refer to the AM reception section
in the DE SSG. |
In order to test for audio reception and noise problems, perform the
following steps:
- Position the car outside of the building with the hood down.
- Duplicate the customer's complaint before trying to diagnose the
system.
- Have the customer demonstrate the condition.
- Test drive the vehicle with the customer.
- Test drive another similar model vehicle with a similar stereo
system in order to do a comparison of the two vehicles.
This step will help to determine if the condition is abnormal.
- Identify the components, their features, and the customer's complaint
before diagnosing the system.
- Determine if any aftermarket equipment has been installed in the
vehicle.
- Disconnect the aftermarket equipment in order to determine if
the customer's complaint still exists.
- Follow GM guidelines in order to reinstall the aftermarket components.
Refer to the DE SSG.
In order to identify a noisy component, perform the following steps:
- Identify the ignition key switch position in which the noise appears,
such as ACC, or KEY ON engine running/not running.
- Remove the fuses one at a time until the complaint condition has
been eliminated.
- Mark the complaint fuse(s) in order to install all fuses and circuit
breakers.
- Identify all systems and components powered by the complaint fuse(s).
Refer to Wiring Systems.
- Disconnect the components which are powered by the complaint fuse(s)
one at a time until the complaint condition has been eliminated and the noisy
component has been identified.
- Inspect the ground integrity of the complaint-causing component.
| • | An interference condition is not necessarily an audible noise. |
| • | Most noises can be found on weak stations near the low end of
the band and are considered to be a normal condition. |
| • | Ignition noise on FM could indicate a possible defective ignition
system. |
| • | Malfunctioning and marginal components, relays, and solenoids
may induce noise and/or poor reception. |
