GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

  1. Disconnect the negative battery cable.
  2. Disconnect the antenna lead-in harness connector at the radio receiver.
  3. Using a J 39200 DMM, measure resistance between the antenna lead-in harness connector and ground.

Is the reading greater than specified?

0.15ohms

Go to Step 10

Go to Step 2

2

  1. Leave the J 39200 DMM connected.
  2. Wiggle the antenna lead-in harness connector at the radio antenna module.

Does the J 39200 DMM indicate intermittent continuity?

--

Go to Step 10

Go to Step 3

3

Inspect the coax cable.

Is the coax cable type RG-58 or RG-59?

--

Go to Step 4

Go to Step 5

4

Is the measured resistance less than the specified value?

0.2ohms

Go to Step 6

Go to Step 8

5

For RG-62 or RG-62M, does the measured resistance approximately equal the specified value?

Less than 3.5ohms

Go to Step 6

Go to Step 8

6

While observing the J 39200 DMM, wiggle the antenna coax.

Does the meter indicate intermittent continuity?

--

Go to Step 7

Go to Step 9

7

  1. Inspect the coaxial cable interconnects for a poor connection or corrosion.
  2. Repair or replace the antenna coaxial circuit as necessary. Refer to Antenna Extension Cable Replacement Rear Window Antenna (U77) for service procedure.

Is the repair complete?

--

Go to Audio Preliminary Diagnosis

--

8

  1. Inspect the coaxial cable interconnects for a poor connection or corrosion.
  2. Repair or replace the antenna coaxial circuit as necessary. Refer to Antenna Extension Cable Replacement (Rear Window Antenna (U77)) for service procedure.

Is the repair complete?

--

Go to Audio Preliminary Diagnosis

--

9

  1. Disconnect the radio antenna module harness connector.
  2. Using a test lamp, backprobe between the radio antenna module harness connector terminal A and terminal B.

Does the test lamp light?

--

Go to Step 12

Go to Step 11

10

Inspect the cable interconnects for a poor connection or corrosion.

Are all connections clean, tight and free of corrosion?

--

Go to Step 11

Go to Step 15

11

Replace the radio antenna module.

Is the repair complete?

--

Go to Audio Preliminary Diagnosis

--

12

Using a test lamp, backprobe between the radio antenna module harness connector terminal A and ground.

Does the test lamp light?

--

Go to Step 13

Go to Step 14

13

Repair poor connection or open in CKT 351.

Is the repair complete?

--

Go to Audio Preliminary Diagnosis

--

14

Repair poor connection or open in CKT 145.

Is the repair complete?

--

Go to Audio Preliminary Diagnosis

--

15

Replace the coaxial cable circuit as necessary. Refer to Antenna Extension Cable Replacement Rear Window Antenna (U77) for service procedure.

Is the repair complete?

--

Go to Audio Preliminary Diagnosis

--