How To Test The Alternator (1992-1995 2.2L Beretta, Cavalier, Corsica, Sunfire)

TEST 3: Checking The Battery Voltage Sense Circuit Wire

NOTE: If your vehicle is a 1995 model year Cavalier or Sunbird, you can skip this section (since the alternator pigtail connector does not have an S terminal).

The voltage regulator inside the alternator needs to sense the battery's voltage as the engine is running.

The alternator accomplishes the 'voltage sensing' thru the wire that connects to the female terminal labeled with the letter S in the illustration above.

An inline fusible link protects the battery voltage sense wire, and we need to check that it's not blown.

We'll do a simple multimeter continuity test to check the integrity of the inline fusible link protecting the voltage sensor wire.

Let's get the ball rolling:

1. 1

   Disconnect the battery negative (-) cable from the battery but leave the positive (+) cable connected to the positive (+) post.
   
   IMPORTANT: Do not proceed to the next steps until you do this first.

2. 2

   Disconnect the 3-wire pigtail connector from the alternator.

3. 3

   Set your multimeter to Ohms mode.

4. 4

   Connect the red multimeter test lead to the battery positive (+) terminal.
   
   IMPORTANT: The multimeter test lead must connect to a clean spot on the battery's positive (+) terminal

5. 5

   Connect the black multimeter test lead to the female terminal labeled with the letter S of the alternator's 3-wire pigtail connector (see the illustration above).

6. 6

   Your multimeter should register continuity, usually an Ohms reading of less than 1 Ohm.

Let's take a look at what your specific test results mean:

CASE 1: The multimeter registered continuity. This is the correct and expected test result and confirms that the battery voltage sense wire's inline fusible link is OK.

Your next step is to go to: TEST 4: Making Sure The Alternator Fuse Is Not Blown.

CASE 2: The multimeter reports the wire has an open-circuit problem (usually by displaying the letters OL). This tells you that the inline fusible link that protects the battery voltage sense wire is blown.

Your next step is to replace the inline fusible link and retest the battery's voltage with the engine running (TEST 1).

TEST 4: Making Sure The Alternator Fuse Is Not Blown

The voltage regulator's field coil circuit receives 12 Volts DC from a dedicated fuse.

For your next test, you'll make sure that the alternator fuse is okay and supplying 10 to 12 Volts DC to the alternator's field coil circuit.

The terminal that delivers voltage (from the fuse) to the alternator is the female terminal labeled with the letter F in the illustration above.

We can easily confirm that the alternator fuse is okay by checking for the presence of 12 Volts at the female terminal labeled with the letter F of the alternator's 3-wire pigtail connector (see illustration above).

NOTE: The alternator fuse is located in the instrument panel fuse box and depending on your vehicle's model year, it'll be called by a different name:

• 1992-1994 2.2L Chevy Cavalier: HTR-A/C Fuse.
• 1996 2.2L Chevy Cavalier: GEN Fuse.
• 1992-1995 2.2L Chevy Beretta: Fuse 4.
• 1992-1995 2.2L Chevy Corsica: Fuse 4.
• 1995 2.2L Pontiac Sunfire: GEN Fuse.

These are the test steps:

1. 1

   Reconnect the negative (-) battery cable to the battery's negative (-) post,.

2. 2

   Disconnect the 3-wire pigtail connector from the alternator.

3. 3

   Connect the black multimeter test lead to the battery negative (-) terminal.
   
   IMPORTANT: The multimeter test lead must connect to a clean spot on the battery's negative (-) terminal

4. 4

   Connect the red multimeter test lead to the female terminal labeled with the letter F of the alternator's 3-wire pigtail connector (see the illustration above).

5. 5

   Have your helper turn the key to the ON position (RUN position) but ask him NOT to crank the engine.

6. 6

   Your multimeter should register 10 to 12 Volts DC.

Let's analyze your test result:

CASE 1: The multimeter registered 10 to 12 Volts DC. This is the correct and expected test result.

Your next and last step is to go to: TEST 5: Checking The Alternator's L Circuit.

CASE 2: The multimeter DID NOT register 10 to 12 Volts DC. Check the alternator fuse to see if its blown.

If the fuse is blown, replace it with a fuse of the same rating and repeat TEST 1.

If the alternator still does not charge the battery, go to: TEST 5: Checking The Alternator's L Circuit.

TEST 5: Checking The Alternator's L Circuit

For your last test, you'll check that the terminal labeled with the letter L of your alternator's 3-wire connector (see illustration above) has 10 to 12 Volts with the key in the ON position.

This circuit does two very important things:

• Illuminates the battery light on your instrument cluster when the alternator is not charging the battery.
• Activates (excites) the alternator's voltage regulator to begin charging the battery.

Let's get started:

1. 1

   Disconnect the alternator's 3-wire connector if it isn't already.

2. 2

   Place your multimeter in Volts DC mode.

3. 3

   Connect the black multimeter test lead to the negative (-) battery terminal.

4. 4

   Turn the key to the ON position but don't crank or start the engine.

5. 5

   With the red multimeter test lead, probe the female terminal labeled with the letter L of your alternator's connector.

6. 6

   Your multimeter should register 10 to 12 Volts DC.

Let's interpret your test result:

CASE 1: The multimeter registered 10 to 12 Volts DC. This is the correct and expected test result.

You can conclude that the alternator is bad if you have:

• Confirmed that battery voltage is below 12.5 Volts DC and continues to fall as the engine runs (TEST 1).
• Confirmed that the inline fusible link that protects the alternator's output wire is not blown (TEST 2).
• Confirmed that the battery voltage sense wire's inline fusible link is not blown (TEST 3).
• Confirmed that the alternator fuse is OK (TEST 4).
• Confirmed in this last test section that the L terminal has 10 to 12 Volts DC.

CASE 2: The multimeter DID NOT register 10 to 12 Volts DC. This result tells you that one of three things have gone wrong:

• The fuse that supplies 12 Volts to the battery (charge) lamp is blown.
• An open-circuit problem has occurred in the L circuit wire between the connector and the instrument panel or fuse box.
• The battery lamp is blown (in the instrument cluster).

Although its beyond the scope of this tutorial to diagnose this issue, your next step is to find out why the L terminal does not have 10 to 12 Volts.

More 2.2L Beretta, Cavalier, Corsica, And Sunfire Diagnostic Tutorials

If this tutorial was helpful, be sure and take a look at all of the 2.2L Beretta, Cavalier, Corsica, And Sunfire diagnostic tutorials in this index:

• GM 2.2L Index Of Articles.

Here's a sample of the tutorials you'll find there:

• How To Test The Thermostat (1992-1997 2.2L Beretta, Cavalier, Corsica, Sunfire).
• How To Test The Fuel Pump (1992-1997 2.2L Beretta, Cavalier, Corsica, Sunfire).
• How To Test The TPS (1992-1997 2.2L Beretta, Cavalier, Corsica, Sunfire).
• How To Test The GM 2.2L Ignition Coil Pack.