How To Test The Turn Signal Switch (Step by Step)

TEST 5: Rear Right Turn Signal Output

IMPORTANT: If you haven't already disabled the air bag system, do so now. You can find the instructions here: Disabling the Air Bag System (SIR).

In this test step, you're gonna' verify that the turn signal switch is sending the activating voltage to the Rear Right turn signal lamps.

Before you start this test, it's important that you have done TESTS 1, 2, and 3 since these tests check the very basics the turn signal switch needs to work properly.

The circuit that you'll be testing is the one labeled with the number 6 of the gray turn signal switch connector.

This is what you'll need to do:

1. Locate the circuit labeled with the number 6 of the turn signal switch's gray connector.
   • Remember, the gray connector has to remain connected to the instrument panel harness during the test.
2. Turn the ignition switch to the ON position.
3. With your multimeter to Volts DC mode probe the wire that corresponds to the number 6 with the red multimeter test lead.
   • Since the gray connector has to remain connected to the instrument panel harness, you need to probe the wire somewhere between the gray connector and the turn signal switch using an appropriate tool (like a Wire Piercing Probe).
4. Ground the black multimeter test lead on a good Ground point.
5. Active the Right turn signal.
6. You're multimeter will register one of two things:
   • A battery voltage (10 to 12 Volts) that flashes ON and OFF.
   • No battery voltage at all.
7. When done, turn the turn signal and ignition switch off.

Let's examine your test results:

CASE 1: The multimeter registered a flashing 10-12 Volts. This is the normal test result and tells you that the turn signal switch is feeding power to the Rear Right turn signal lamps.

The next step is to check that the Front Left turn signal lamps are getting power from the turn signal switch. Go to: TEST 6: Front Left Turn Signal Output.

CASE 2: The multimeter DID NOT register a flashing 10-12 Volts. Re-check your connections and repeat the test.

If the multimeter still does not show you any DC voltage, then the turn signal switch is bad and needs to be replaced.

TEST 6: Front Left Turn Signal Output

IMPORTANT: If you haven't already disabled the air bag system, do so now. You can find the instructions here: Disabling the Air Bag System (SIR).

In this test step, you're gonna' check that the turn signal switch is feeding power to the Front Left turn signal lamps.

The circuit that you'll be testing is the one labeled with the number 7 of the Black turn signal switch connector.

Remember: You won't be probing the front of the connector since the Black turn signal switch connector has to remain connected to its instrument panel harness connector. What you'll is probe the wire (with a wire piercing probe or similar tool) somewhere between the turn signal switch and the black connector.

OK, this is what you'll need to do:

1. Identify the circuit labeled with the number 7 of the black connector.
   • The black connector must remain connected to the instrument panel harness connector at all times during this test.
2. Turn the ignition switch to the ON position.
3. Once again, your multimeter must be set to Volts DC mode:
   • Probe the wire that corresponds to the number 7 with the red multimeter test lead.
4. Ground the black multimeter test lead on a good Ground point.
5. Activate the Left Hand turn signal lamps
6. You're gonna' see one of the following test results:
   • A battery voltage (10 to 12 Volts) that flashes ON and OFF.
   • No battery voltage at all.
7. When done, turn the turn signal and ignition switch off.

Let's examine your test results:

CASE 1: Your multimeter registered voltage (10 to 12 Volts) flashing ON and OFF. This is the normal and expected test result and tells you that the turn signal switch is activating the Front Left turn signal lamps.

The next step is to Rear Left turn signal lamps output, go to: TEST 7: Rear Left Turn Signal Output.

CASE 2: Your multimeter DID NOT register voltage (10 to 12 Volts) at all. Re-check all of your multimeter connections and repeat the test one more time.

If still NO voltage, then the turn signal switch is bad (internally) and needs to be replaced.