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Home >> GMC >> 1991 >> Value Van 7.4 N >> Repair and Diagnosis >> External Pages >> Different car >> Section 82 (Engine Controls - Tests W/Codes - Body Control Computer) >> Self-Diagnostic Tests >> Test 91A - Poor Sound Quality From All Speakers

Test 91A - Poor Sound Quality From All Speakers

WARNING: This page is about a different car, the 1995 Plymouth Voyager, 1995 Plymouth Grand Voyager, 1995 Dodge Grand Caravan, 1995 Dodge Caravan, and 1995 Chrysler Town & Country. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION: Always turn ignition off prior to disconnecting any module connector.
NOTE: For connector terminal identification, see CONNECTOR IDENTIFICATION  . For appropriate wiring diagram, see WIRING DIAGRAMS  section at the end of this article. Perform TEST VER-1B after each repair.
NOTE: Radio must remain on during this test.
  1. Turn radio on. Gain access to back of radio. Using scan tool in voltmeter mode, backprobe radio Black connector terminal No. 1 (Dark Green/Red wire). If voltage is less than 10 volts, go to TEST 91B. If voltage is more than 10 volts, go to next step.
  2. Disconnect backprobe. Remove speaker power relay (first relay from left, bottom row) from micro relay center, located behind center console. Go to next step.
  3. Using scan tool in voltmeter mode, check voltage on speaker power relay connector (Dark Green/Red wire). If voltage is less than 10 volts, repair open Dark Green/Red wire. If voltage is more than 10 volts, go to next step.
  4. Using scan tool in ohmmeter mode, check resistance of speaker power relay connector (Black wire). If resistance is more than 5 ohms, repair open Black wire. If resistance is less than 5 ohms, go to next step.
  5. Using scan tool in voltmeter mode, check voltage on speaker power relay connector (Red wire). If voltage is less than 10 volts, repair open Red wire. If voltage is more than 10 volts, go to next step.
  6. Connect a jumper wire between speaker power relay connector (Red wire and Red/Light Green wire). If speaker sound quality improves, replace speaker power relay. If speaker sound quality does not improve, go to next step.
  7. Disconnect jumper wire. Reinstall speaker power relay. Disconnect radio choke (noise suppressor) connector. Radio choke connector is located behind left side knee panel, between speaker power relay (Red/Light Green wire) and speakers (Black/Red wire). Go to next step.
  8. Using scan tool in voltmeter mode, check voltage on radio choke connector terminal No. 1 (Red/Light Green wire). If voltage is less than 10 volts, repair open Red/Light Green wire. If voltage is more than 10 volts, go to next step.
  9. Connect a jumper wire between radio choke connector terminals No. 1 (Red/Light Green wire) and No. 2 (Black/Red wire). If speaker sound quality improves with jumper wire connected, replace radio choke. If speaker sound quality does not improve, repair open Black/Red wire.
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