GM Service Manual Online
For 1990-2009 cars only

Radio Poor Reception Rear Window Antenna

Step

Action

Value(s)

Yes

No

1

Did you perform the radio/audio diagnostic system check?

--

Go to Step 2

Go to Radio/Audio System Check

2

Is the reception weak or noisy only when the rear defogger is on?

--

Go to Step 6

Go to Step 3

3

Connect the base of the rear defogger/antenna grid to chassis ground.

Does the reception improve?

--

Go to Step 4

Go to Step 5

4

Repair the radio antenna module case ground.

Is the repair complete?

--

Go to Radio/Audio System Check

--

5

    • Turn the ignition switch to the RUN position.
    • Turn the radio to the ON position.
    • Measure the voltage between the rear defogger/antenna grid connector C2 terminal 1 and ground.

Is the voltage within the specified range?

10-15 V

Go to Step 6

Go to Step 7

6

Test the rear defogger grid for a open. Refer to Defogger Grid Lines Diagnosis .

Was a open found?

--

Go to Step 8

Go to Step 9

7

Test CKT 145 (DK GRN) for a open or short to ground.

Was a open or short to ground found?

--

Go to Step 10

Go to Step 11

8

Replace the rear window. Refer to Rear Window Replacement

Is the repair complete?

--

Go to Radio/Audio System Check

--

9

Replace the radio antenna module. Refer to Radio Antenna Module Replacement

Is the repair complete?

--

Go to Radio/Audio System Check

--

10

Repair the open or short to ground in CKT 145 (DK GRN).

Is the repair complete?

--

Go to Radio/Audio System Check

--

11

Replace the radio. Refer to one of the following procedures:

  1. Radio Replacement
  2. Radio Replacement
  3. Radio Replacement

Is the repair complete?

--

Go to Radio/Audio System Check

--