GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Perform diagnostic testing per BRAKES and ENGINE CONTROLS. This testing will identify problems with the vehicle speed sensor or the speedo adapter.

Is the problem resolved?

Go to Step 2

Go to Step 3

2

System is operating properly.

Is the repair complete?

System OK

--

3

  1. Disconnect the connector at the instrument cluster.
  2. Disconnect the connector at the speedo adapter.
  3. Connect a J39200 between the instrument cluster connector terminal D for CKT 42 (WHT) and CKT 422 (WHT) and ground.

Does the DMM indicate continuity?

Go to Step 4

Go to Step 5

4

Locate and repair the short to ground on CKT 42 (WHT) and CKT 422 (WHT) between the speedo adapter and the instrument cluster.

Is the repair complete?

System OK

--

5

Connect a J39200 between the instrument cluster connector terminal D and the speedo adapter connector terminal B8 for CKT 42 (WHT) and CKT 422 (WHT).

Does the DMM indicate continuity?

Go to Step 6

Go to Step 7

6

Replace the instrument cluster. Refer to Instrument Cluster Replacement .

Is the repair complete?

System OK

--

7

Locate and repair the open in the CKT 42 (WHT) and CKT 422 (WHT) between the speedo adapter and the instrument cluster.

Is the repair complete?

System OK

--