How To Test The Alternator (1992-2001 2.2L Toyota Camry)

TEST 2: Checking The Continuity Of The Bat (+) Cable

All the electrical power generated by the alternator, whether to charge the battery or power your Toyota Camry's electrical systems, must pass through a 100 Amp mega fuse before reaching the battery.

This 100 Amp ALT fuse is located in the under-hood fuse/relay box (Junction Block 2), which you'll find on the left inner fender in the engine compartment.

If this fuse is blown, the alternator might still be working, but its output will never make it to the battery.

We're gonna do a simple multimeter continuity test on the BAT+ cable to check the condition of the 100A ALT fuse.

NOTE: In the image above, you'll see that the BAT+ cable is disconnected from the alternator. This is only for demonstration purposes to explain the test connections. In practice, the BAT+ cable must remain connected to the alternator during the test.

These are the test steps:

1. 1

   Disconnect the battery negative (-) cable terminal from the battery negative post. The positive cable remains connected.
   
   IMPORTANT: Don't continue to the next step without first disconnecting the negative cable from the negative battery post.

2. 2

   Set your multimeter to Ohms mode.

3. 3

   Connect the red multimeter test lead to the stud on the rear of the alternator.
   
   The BAT + cable, which connects to the battery positive (+) terminal, is the cable that connects here.

4. 4

   With the black multimeter test lead probe the center of the battery positive (+) post on your Toyota Camry's battery.

5. 5

   You'll get one of two results.
   
   1.) No Continuity: The multimeter will indicate a reading of OL (which means over limit).
   
   2.) Continuity: Your multimeter will register an Ohms reading of 0.5 Ohms or less.

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

CASE 1: Your multimeter registered continuity. This is the correct and expected test result.

This test result indicates that the 100 Amp mega-fuse protecting this circuit is OK and not blown.

The next step is to go to: TEST 3: Checking The Alternator Fuse.

CASE 2: Your multimeter DID NOT register continuity. This result tells you that the 100 amp mega fuse is blown and this will keep the alternator from charging the battery.

Replace the fuse and retest.

TEST 3: Checking The Alternator Fuses

For our final test, we'll check that terminals 1 and 3 of the alternator's 3-wire connector are receiving 10 to 12 Volts.

• Terminal 3 should always have 10 to 12 Volts, regardless of the key position.
• Terminal 1 will only have power when the key is in the ON or START position.

We'll use a multimeter to check the voltage at these terminals.

Let's get started:

1. 1

   Reconnect the battery to its battery negative (-) cable, that you disconnected in the previous test.

2. 2

   Disconnect the alternator's 3-wire connector.

3. 3

   Place your multimeter in Volts DC mode.

4. 4

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

5. 5

   Probe terminal 3 with the red multimeter test lead.
   
   Terminal 3 should connect to a white (WHT) wire.

6. 6

   The multimeter should register 10 to 12 Volts.
   
   Terminal 3 should have power present at all times (whether the key is ON or not).

7. 7

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

8. 8

   Probe terminal 1 with the red multimeter test lead.
   
   Terminal 1 should connect to a yellow (YEL) wire.

9. 9

   The multimeter should register 10 to 12 Volts DC.
   
   Terminal 1 should have power only with the key in the ON and RUN positions.

Let's examine your test result:

CASE 1: Power is present in terminals 1 and 3. This is the correct and expected test result.

You can conclude that the alternator is bad and needs to be replaced if you have:

• Confirmed that the battery's voltage is 12.5 or less with the engine running (TEST 1).
• Confirmed that the 100 Amp ALT fuse is OK (TEST 2).
• Confirmed in this test section that terminals 1 and 3 (of the alternator's 3-wire connector) have 10 to 12 Volts present (this test section).

CASE 2: Power IS NOT present in terminal 1. This usually tells you that the IGN Fuse is blown.

The IGN fuse is in the under-dash fuse box:

• 1992-1996 Camry: This fuse is a 7.5A fuse.
• 1997-2001 Camry: This is a 5A fuse.

If the fuse is blown, replace it with another of the same amperage rating and start the car and check to see if the alternator is now charging the battery by repeating TEST 1.

CASE 3: Power IS NOT present in terminal 3. This usually tells you that the ALT-S Fuse is blown.

The ALT-S fuse is in the under-hood fuse box:

• 1992-1996 Camry: This fuse is a 7.5A fuse.
• 1997-2001 Camry: This is a 5A fuse.

If the fuse is blown, replace it with another of the same amperage rating and start the car and check to see if the alternator is now charging the battery by repeating TEST 1.

More 2.2L Toyota Camry Tutorials

You can find a complete list of 2.2L Toyota Camry tutorials and wiring diagrams in this index:

• 2.2L Toyota Camry And Celica Index of Articles.

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

• How To Test Engine Compression (1990-2001 2.2L Toyota Camry, Celica).
• How To Test The TPS With A Multimeter (1997-2001 2.2L Toyota Camry).
• How To Test For A Blown Head Gasket (1990-2001 2.2L Toyota Camry, Celica).
• How To Test The Throttle Position Sensor (1992-1996 2.2L Toyota Camry).