Speakers Inoperative - One or More. Pontiac Firebird 1999

Disconnect the amplifier connector.
Turn the ignition switch to the ACCY position.
Turn the radio on.
Insert a cassette or compact disc from J 39916-A. Refer to J 39916-A
Set the radio balance and fade controls to the detent (center) position.
Set the radio volume at the normal listening level.
Measure and record the AC voltage between the amplifier connector terminals E2 and E3 with a DMM while playing the combination test tone from the cassette or the compact disc.
Measure and record the AC voltage between the amplifier connector terminals E1 and F1.

Are the recorded voltages approximately the same?

Go to Step 3

Go to Step 5

Perform the following:

•	Inspect for a poor connection at the amplifier, radio and appropriate speaker.

•	Verify continuity of appropriate audio wires from the radio to the amplifier.

•	Verify continuity of appropriate speaker wires from the amplifier to the speaker.

•	Verify power and ground circuit voltages are present at the amplifier by measuring between the appropriate terminals on the amplifier connector.

•	Repair wiring as necessary.

Did you find and correct the condition?

Go to Step 8

Go to Step 4

Replace the audion amplifier. Refer to Radio Speaker Amplifier Replacement .

Is the repair complete?

Go to Step 8

Backprobe the radio connector C1 between terminals 1 and 2 and record AC voltage with a DMM.
Backprobe the radio connector C1 between terminals 3 and 4 and record the AC voltage.

Are the recorded voltages approximately the same?

Go to Step 6

Go to Step 7

If the left speaker is inoperative, repair the open in the circuit 118 or circuit 201 between the radio and the amplifier.
If the right speaker is inoperative, repair the open in the circuit 117 or circuit 200 between radio and amplifier.

Is the repair complete?

Go to Step 8

If the left speaker is inoperative, inspect for the following conditions:

•	A short to B+ or ground in circuits 118 and 201 between the radio and the amplifier

•	A poor connection at the radio connector C1 terminal 1 and terminal 2

If the right speaker is inoperative, inspect for the following conditions:

•	A short to B+ or ground in circuits 117 and 200 between the radio and the amplifier

•	A short to B+ or ground at the radio connector C1 terminal 3 and terminal 4

Replace the radio if the inspections are OK. Refer to Radio Replacement

Is the repair complete?

Go to Step 8

Turn the ignition switch to the OFF position.
Reconnect all connectors/components removed.

Have all the repairs been made?

Speakers Inoperative - One or More Tweeter or Midrange at front

Step	Action	Value(s)	Yes	No
1	Was the entire Radio/Audio System System Check performed?	--	Go to Step 2	Go to Radio/Audio System Check
2	Turn the ignition switch to the ACCY position. Turn the radio on. Insert a cassette or compact disc from J 39916-A . Set the radio balance and fade controls to the detent (center) position. Set the radio volume at the normal listening level. Play the combination test tone from the cassette or CD. Backprobe the speaker assembly connector between terminals A and B (tweeter) or terminals C and D (midrange) with a DMM. Is the voltage greater than 0V AC?	> 0V AC	Go to Step 3	Go to Step 4
3	Inspect for a poor connection at the inoperative speaker assembly. Replace the speaker if the connection is OK. Refer to Radio Front Speaker Replacement Is the repair complete?	--	Go to Step 7	--
4	Turn the ignition switch to the OFF position. Disconnect the amplifier connector. Probe the amplifier connector between the feed (+) and return (-) circuits of the inoperative speaker with a DMM. Is the resistance approximately 2-4ohms?	2-4ohms	Go to Step 5	Go to Step 6
5	Inspect the speaker feed (+) and the return (-) circuits for a short to B+ or ground between the speaker assembly and the amplfier. Inspect for a poor connection at the amplifier. Replace the amplifier if the connections are OK. Refer to Radio Speaker Amplifier Replacement Is the repair complete?	--	Go to Step 7	--
6	Inspect for a poor connection at the speaker. Repair open or a poor connection in the speaker assembly feed or the return circuit. Is the repair compete?	--	Go to Step 7	--
7	Turn the ignition switch to the OFF position. Reconnect all connectors/components removed. Have all the repairs been made?	--	Go to Radio/Audio System Check	--

Speakers Inoperative - One or More Both Rear

Step

Action

Value(s)

Yes

Was the entire Radio/Audio system System Check performed?

Go to Step 2

Disconnect the amplifier connector.
Turn the ignition switch to ACCY.
Turn the radio on.
Insert a cassette or compact disc from J 39916-A .
Set the radio balance and fade controls to the detent (center) position.
Set the radio volume at the normal listening level.
Play the combination test tone from the cassette or CD.
Use a DMM in order to measure the AC voltage between the amplifier connector terminals E6 and E7.
Measure the AC voltage between the amplifier connector terminals E4 and E5.

Record the voltage

Are the voltage readings approximately the same?

> 0V AC

Go to Step 3

Go to Step 4

Inspect for a poor connection at the amplifier connector terminals E6 and E7 (left) or terminals E4 and E5 (right).
Replace the amplifier if the connection is OK. Refer to Radio Speaker Amplifier Replacement

Is the repair complete?

Use a DMM in order to backprobe the radio connector C3 between terminal 19 and terminal 20
Probe the radio connector C3 between the terminal 17 and terminal 18.
Record the voltage reading.

Is the voltage approximately the same?

> 0V AC

Go to Step 6

For left inoperative speakers, repair the open in circuit 116 or circuit 199 between the radio and amplifier.
For right inoperative speakers, repair the open in circuit 115 or circuit 46 between the radio and amplifier.

Is the repair complete?

If the left speaker is inoperative, inspect the for the following conditions:

•	A short to B+ or ground in circuits 116 or 199

•	A poor connection at the radio connector C3 terminal 19 and terminal 20

If the right speaker is inoperative, inspect for the following conditions:

•	A short to B+ or ground in circuits 115 and 46.

•	A poor connection at the radio connector C3 terminal 17 and terminal 18.

Replace the radio if none of these conditions exist. Refer to Radio Replacement

Is the repair complete?

Turn the ignition switch to the OFF position.
Reconnect all connectors/components removed.

Have all the repairs been made?

Speakers Inoperative - One or More No sound, radio oper. normally

Step

Action

Value(s)

Yes

Was the entire Radio/Audio System System check performed?

Go to Step 2

Disconnect the amplifier connector.
Turn the ignition switch to the ACCY position.
Turn the radio on.
Insert a cassette or compact disc from J 39916-A .
Set the radio balance and fade controls to the detent (center) position.
Set the radio volume at the normal listening level.
Play the combination test tone from the cassette or CD.
Backprobe the speaker assembly connector between terminals E6 and E7.
Record the voltage reading.

Is the voltage greater than 0V AC?

> 0V AC

Go to Step 3

Go to Step 5

Perform the following:

•	Inspect for a poor connection at the amplifier, radio and appropriate speaker.

•	Verify continuity of appropriate audio wires from the radio to the amplifier.

•	Verify continuity of appropriate speaker wires from the amplifier to the speaker.

•	Verify power and ground circuit voltages are present at the amplifier by measuring between the appropriate terminals on the amplifier connector.

•	Repair wiring as necessary.

Go to Step 6

Replace the audio amplifier. Refer to Radio Speaker Amplifier Replacement

Is the repair complete?

Go to Step 6

Replace the radio. Refer to Radio Replacement

Is the repair complete?

Go to Step 6

Turn the ignition switch to the OFF position.
Reconnect all connectors/components removed.

Have all the repairs been made?

Speakers Inoperative - One or More one front tweeter inop

Step

Action

Value(s)

Yes

Was the entire Radio/Audio System System Check performed?

Go to Step 2

Disconnect the connector C240.
Turn the ignition switch to the ACCY position.
Turn the radio on.
Insert a cassette or compact disc from J 39916-A .
Set the radio balance and fade controls to the detent (center) position.
Set the radio volume at the normal listening level.
Play the tweeter test tone from the cassette or CD.
Use a DMM in order to measure the AC voltage between C240 connector terminal B and terminal C (left) or terminal F and terminal G (right).

Is the voltage greater than 0V AC?

> 0V AC

Go to Step 3

Go to Step 4

Reconnect the connector C240.
Disconnect the inoperative speaker connector.
Use a DMM in order to measure the AC voltage between the speaker connector terminal A and terminal B on the harness side.

Is the voltage greater than > 0V AC?

> 0V AC

Go to Step 6

•	If the left front tweeter is inoperative repair an open or a poor connection in circuit 118 or circuit 201 between the radio and C240.

•	If the right front tweeter is inoperative repair an open or poor connection in circuit 117 or circuit 200 between the radio and C240.

Is the repair complete?

Inspect for a poor connection at the speaker connector terminals A and B.
Replace the speaker if the connection is OK. Refer to Speaker Replacement

Is the repair complete?

•	If the left front tweeter is inoperative repair an open in circuit 118 or circuit 201 between the speaker and C240.

•	If the right front tweeter is inoperative repair an open in circuit 117 or circuit 200 between the speaker and C240.

Is the repair complete?

Turn the ignition switch to the OFF position.
Reconnect all connectors/components removed.

Have all the repairs been made?

Speakers Inoperative - One or More one rear tweeter inop

Step

Action

Value(s)

Yes

Was the entire Radio/Audio System System Check performed?

Go to Step 2

Disconnect the amplifier connector.
Turn the ignition switch to the ACCY position.
Turn the radio on.
Insert a cassette or compact disc from J 39916-A .
Set the radio balance and fade controls to the detent (center) position.
Set the radio volume at the normal listening level.
Play the combination test tone from the cassette or CD.
With a DMM backprobe the inoperative speaker connector between terminal A and terminal B on the harness side.

Is the voltage greater than 0V AC?

> 0V AC

Go to Step 3

Go to Step 4

Inspect for a poor connection at the speaker terminal A and terminal B.
Replace the speaker if the connection is OK. Refer to Speaker Replacement

Is the repair complete?

•	If the left rear tweeter is inoperative perform the following actions:

1.	Inspect for an open in circuit 199 between speaker terminal B and S305.

2.	If OK, repair the open in circuit 116 between speaker terminal A and S302.

•	If the right rear tweeter is inoperative perform the following actions:

1.	Inspect for the open in circuit 46 between speaker terminal B and S300.

2.	If OK, repair an open in circuit 115 between the terminal A and S301.

Is the repair complete?

Turn the ignition switch to the OFF position.
Reconnect all connectors/components removed.

Have all the repairs been made?