Step
| Action
| Value(s)
| Yes
| No
|
1
|
- Inspect all connectors from the radio to the sound processor interface
and to the radio speaker amplifier.
- Look for loose connections, bent pins, corrosion or other damage
to the connector pins.
Are all connectors and connector pins OK?
| --
|
Go to Step 3
|
Go to Step
2
|
2
| Repair the connector or connector pins as needed.
Did the noise go away?
| --
|
Go to Step
7
|
Go to Step 3
|
3
|
- Remove the ground wire pin from the amplifier connector.
- Connect a new wire from the amplifier pin connector to a known
good clean chassis ground.
- Verify the ground using the DMM.
Did the noise go away?
| --
|
Go to Step
7
|
Go to Step 4
|
4
| Disconnect the audio input circuits from the amplifier connector, leaving
B+ and the ground wires connected.
Did the noise go away?
| --
|
Go to Step
5
|
Go to Step 6
|
5
| Repair, reroute or replace the audio input lines.
Is the repair or replacement complete?
| --
|
Go to Step 7
| --
|
6
| Replace the radio speaker amplifier. Refer to
Radio Speaker Amplifier Replacement
in Entertainment.
Is the replacement complete?
| --
|
Go to Step
7
| --
|
7
|
- Connect all connectors and components that were disconnected.
- Verify that there is no noise in the speakers.
Is there noise in the speakers?
| --
|
Go to Step
1
| System OK
|
Step
| Action
| Value(s)
| Yes
| No
|
DEFINITION:
This table is used for diagnosing noise complaints that enter through the
power supply.
|
1
|
- Temporarily remove the B+ and ground leads from the radio connector.
- Install a temporary set of B+ and ground leads to the radio connector.
- Attach the other end of the temporary leads directly to the battery.
Did the noise go away?
| --
|
Go to Step
3
|
Go to Step 2
|
2
|
- Restore the radio connections as they were before.
- Temporarily remove the B+ and ground leads from the amplifier
connector.
- Install a temporary set of B+ and ground leads to the amplifier
connector.
- Attach the other end of the temporary leads directly to the battery.
Did the noise go away?
| --
|
Go to Step
5
|
Go to Step 7
|
3
|
- The noise is getting into the system through the radio.
- Temporarily move the B+ lead to the amplifier fuse.
Did the noise go away?
| --
|
Go to Step
4
|
Go to Step 7
|
4
| Reroute the B+ lead or install new wires routing them away from the
other circuits.
Is the repair complete?
| --
|
Go to Step
14
| --
|
5
|
- The noise is getting into the system through the amplifier.
- Temporarily move the B+ lead to the radio fuse.
Did the noise go away?
| --
|
Go to Step
6
|
Go to Step 7
|
6
| Reroute the B+ lead or install new wires routing them away from the
other circuits.
Is the repair complete?
| --
|
Go to Step
14
| --
|
7
| Is the noise related to the activation or operation of a switch or accessory?
| --
| Go to
Speaker Noise - Accessory
.
|
Go to Step 8
|
8
| Is the noise
only present when the engine is running?
| --
| Go to
Speaker Noise - Accessory
.
|
Go to Step
9
|
9
|
- Isolate the noisy circuit by removing fuses, relays or circuit
breakers until the noise stops.
- Once you have located the noisy circuit, disconnect components
one by one until the noise stops.
- Once the isolated component is found, replace the component.
Did the noise go away?
| --
|
Go to Step
14
|
Go to Step 10
|
10
|
- Reroute audio harnesses away from the suspect component and harness.
- Remove the audio harness from the same harness bundles containing
the suspected noise source.
Did the noise go away?
| --
|
Go to Step
14
|
Go to Step 11
|
11
|
- If the suspected noisy component shares the same ground as an
audio system component, establish a new clean ground connection for that component.
- If the grounds are routed together, separate them out of the harness
bundle.
- Rap the suspected component's B+ lead with foil or metal tape.
Connect it to one end of a braided ground strap secured with harness tape.
- Ground the other end of the braided ground strap to a known good
clean ground.
Did the noise go away?
| --
|
Go to Step
14
|
Go to Step 12
|
12
|
- Locate the B+ lead for the suspected noisy component.
- Install a noise filter (Use one that is recommended by the auto
manufacturer) in the B+ circuit.
- If the filter is polarity sensitive, install the filter with the
(-) toward the suspected component.
- If the filter has a ground wire for connection, test for best
operation with and then without the ground connected.
Did the noise go away?
| --
|
Go to Step
14
|
Go to Step 13
|
13
| Call the auto manufacturer's technical assistance center for further
assistance.
| --
| --
| --
|
14
|
- Connect all connectors and components that were disconnected.
- Verify that the radio operates properly and that there is no type
of noise present?
Does the radio operate properly?
| --
| System OK
|
Go to Step
1
|
Step
| Action
| Value(s)
| Yes
| No
|
DEFINITION:
This table is used for diagnosing noise complaints that enter through the
radio antenna.
|
1
|
- Check all coaxial connectors, particularly on multipiece antenna
coax systems for corrosion and tightness.
- Reroute the coax cable away from other electrical components.
did the noise go away?
| --
|
Go to Step
6
|
Go to Step 2
|
2
|
- Make sure that the radio connector is clean.
- Attach a braided ground strap to the metal outside jacket of the
connector with harness tape.
- Attach the other end of the ground strap to a known good clean
ground.
Did the noise go away?
| --
|
Go to Step
6
|
Go to Step 3
|
3
|
- Cut the radio ground wire 17 cm (8 in.) from the radio
connector.
- Attach a braided ground strap to the radio case.
- Attach the 8 inch section of ground wire from the radio connector
to the radio case.
- Attach the other end of the braided ground strap to a known good
clean chassis ground.
Did the noise go away?
| --
|
Go to Step
6
|
Go to Step 4
|
4
|
- Find an old piece of coax cable and assemble an "RF Sniffer."
The following procedures explain how to assemble an RF sniffer:
| • | Take an old antenna and cut the antenna mast from the coax cable. |
| • | Cut back about .75 inches of the rubber jacket insulation exposing
the inner braided ground shield. |
| • | Cut back about .5 inches of the inner braided ground shield exposing
the inner conductor. |
| • | Connect the plug end into the radio antenna jack. |
- Use the RF sniffer to search for RF hot spots.
- Move the tip of the RF sniffer, which is the exposed inner conductor,
around the areas of the suspected noise source.
- The noise will be the loudest when you are on the source.
Were there any hot spots found?
| --
|
Go to Step
5
| Go to
Speaker Noise
.
|
5
| Replace the suspected hot spot component.
Is the replacement complete?
| --
|
Go to Step
6
| --
|
6
|
- Connect all connectors and components that were disconnected.
- Verify that the radio operates properly and that there are no
noises present.
Does the radio operate properly?
| --
| System OK
|
Go to Step
1
|
