TEST 4: Testing The START Signal (Anti-Theft Relay)
So far you have:
- Confirmed that the starter motor does crank the engine but only when using a remote start switch (TEST 1).
- That the starter motor is not receiving a START signal (TEST 2).
In this test section, we're gonna' make sure that the anti-theft relay is receiving 10 to 12 Volts DC from the ignition switch.
Specifically, we'll be making sure that the female terminal labeled A2, of the anti-theft relay's electrical connector, has 10 to 12 Volts when turning the key to the START position.
To find the location of the anti-theft relay, see this section: Location Of The Anti-Theft Relay.
Let's get testing:
- 1
Locate and remove from the anti-theft relay from its location.
- 2
Disconnect the anti-theft relay from its connector.
- 3
Place your multimeter in Volts DC mode.
- 4
Connect the black multimeter test lead to the battery negative (-) terminal.
- 5
With the red multimeter test lead, probe the female terminal labeled A2 in the photo above.
- 6
Have your helper turn the key to the START position.
- 7
Your multimeter should register 10 to 12 Volts DC.
Let's examine your test result:
CASE 1: The multimeter registered 10 to 12 Volts. This is the correct test result.
With this test result you can conclude that the ignition switch is OK and sending the START signal to terminal A2.
Your next test is to check that the park-neutral safety switch is functioning correctly. Go to: TEST 5: Testing The Park-Neutral Safety Switch Signal (Anti-Theft Relay).
CASE 2: The multimeter DID NOT register 10 to 12 Volts. This test result usually tells you that the ignition switch is not sending a START signal to the anti-theft relay.
The most likely cause of this missing 12 Volts DC is a bad ignition switch.
TEST 5: Testing The Park-Neutral Safety Switch Signal (Anti-Theft Relay)
In the previous test you confirmed that the ignition switch is sending 12 Volts to terminal A2 of the anti-theft relay's connector.
Now we're gonna' check that female terminal labeled C2 has 10 to 12 Volts when turning the key to the START position.
If 10 to 12 Volts are not present in the C2 terminal, then you can conclude that the park/neutral safety switch has a problem (and behind the starter motor's no-crank issue).
Let's get testing:
- 1
Place your multimeter in Volts DC mode.
- 2
Connect the black multimeter test lead to the battery negative (-) terminal.
- 3
With the red multimeter test lead, probe the female terminal labeled C2 in the photo above.
- 4
Have your helper turn the key to the START position.
- 5
Your multimeter should register 10 to 12 Volts DC.
Let's examine your test result:
CASE 1: The multimeter registered 10 to 12 Volts. This is the correct test result.
With this test result you can conclude that the automatic transmission's park/neutral safety switch is OK.
Your next step is to bypass the anti-theft relay with a jumper wire. For this test go to: TEST 6: Bypassing The Anti-Theft Relay.
CASE 2: The multimeter DID NOT register 10 to 12 Volts. This missing voltage, from the park/neutral safety switch, will cause the anti-theft relay to not activate and the starter motor will not crank the engine.
The most likely cause of these missing 12 Volts are:
- Fuse 11 of the dash panel fuse box is blown (1995-1997 Lumina and Monte Carlo).
- Fuse 7 of the dash panel fuse box is blown (1998-1999 Lumina and Monte Carlo).
- A misadjusted park/neutral safety switch.
- A bad park/neutral safety switch.
- A damaged park/neutral safety switch.
- The park/neutral safety switch connector is loose, broken, or damaged.
Your next step is to check Fuse 7 (or Fuse 11) of the dash panel fuse box. If it's blown, replace it and repeat the test.
If the fuse is not blown, your next step is to test the automatic transmission's park/neutral safety switch.
