For 1990-2009 cars

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
Schematic Reference: Exterior Lights Schematics Connector End View Reference: Lighting Systems Connector End Views
Notice: Do not insert test equipment probes (DVOM etc.) into any connector or fuse block terminal. The diameter of the test probes will deform most terminals. A deformed terminal will cause a poor connection, which will result in a system failure. Always use the J-35616 GM-Approved Terminal Test Kit in order to front probe terminals. Do not use paper clips or other substitutes to probe terminals. When using the J-35616 GM-Approved Terminal Test Kit, ensure the terminal test adapter choice is the correct size for the connector terminal. Do not visually choose the terminal test adapter because some connector terminal cavities may appear larger than the actual terminal in the cavity. Using a larger terminal test adapter will damage the terminal. Refer to the J-35616 GM-Approved Terminal Test Kit label on the inside of the J-35616 GM-Approved Terminal Test Kit for the correct adapter along with the connector end view for terminal size.
1 | Inspect fuse Ef13. Is fuse Ef13 open? | -- | Go to Step 2 | Go to Step 3
2 |

1. Inspect for a short circuit and repair it, if necessary.
2. Replace the fuse.

Did you find and correct the condition?

--

System OK

--

3 | Use a voltmeter to measure the voltage at fuse Ef13. Does the voltage at fuse Ef13 measure within the specified range? | 11-14 V | Go to Step 5 | Go to Step 4
4 | Repair the power supply circuit for fuse Ef13. Did you complete the repair? | -- | System OK | --
5 |

1. Press the brake pedal.
2. Inspect the positive terminals of the bulb sockets with a test lamp.

Does the test lamp illuminate?

--

Go to Step 6

Go to Step 8

6 | Connect an ohmmeter between ground and the stop lamp ground terminal. Is the resistance equal to the specified value? | 0 ohms | Go to Step 8 | Go to Step 7
7 | Repair the ground circuit. Did you complete the repair? | -- | System OK | --
8 |

1. Disconnect the wiring connector from the brake switch.
2. Press the brake pedal.
3. Use an ohmmeter to check continuity between terminals 2 and 4.

Is the resistance equal to the specified value?

0 ohms

Go to Step 10

Go to Step 9

9 | Replace the brake switch. Did you complete the replacement? | -- | System OK | --
10 |

1. Disconnect the brake switch electrical connector.
2. Measure the voltage at terminal 2.

Does the voltage measure within the specified range?

11-14 V

Go to Step 12

Go to Step 11

11 | Repair the open circuit between the fuse Ef13 and the brake switch. Did you complete the repair? | -- | System OK | --
12 | Repair the open circuit between the brake switch and the stop lamps. Did you complete the repair? | -- | System OK | --