GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

  1. Disconnect the generator connector.
  2. Turn the ignintion switch to the RUN position.
  3. Using the DMM, measure the voltage between terminal F of the generator connector and a known good ground.

Is the voltage reading within the specified range?

B+

Go to Step 3

Go to Step 2

2

Locate and repair an open or a high resistance in CKT 41.

Is the repair complete?

--

Go to Step 8

--

3

Using the DMM, measure the voltage from the BAT terminal of the generator to a known good ground.

Is the voltage reading within the specified range?

B+

Go to Step 5

Go to Step

4

Locate and repair an open or a high resistance in CKT1.

Is the repair complete?

--

Go to Step 8

--

5

  1. Connect the generator.
  2. Turn all accessories OFF.
  3. Run the engine at fast idle.
  4. Using the DMM, measure the voltage across the battery.

Is the voltage reading within the specified range?

13.5-15.5 V

Go to Step 7

Go to Step 6

6

Repair or replace the generator. Refer to Generator Replacement .

Is the repair or replacement complete?

--

Go to Step 8

--

7

  1. Load test the generator. Refer to Generator Assembly Check .
  2. If the generator is OK, replace the battery. Refer to Battery Replacement .

--

Go to Step 8

--

8

  1. Connect all connectors and components that were disconnected.
  2. Verify that the charging circuit works properly.

Does the charging circuit work properly?

--

System is OK

Go to Step 1