For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Interior Lights Dimming Schematics DEFINITION: Interior lamps dimming is inoperative.
1 | Did you perform the Lighting System Diagnostic System Check? | Go to Step 2 | Go to Diagnostic System Check - Lighting Systems
2 |

1. Turn on the ignition.
2. Turn the headlamp switch to the PARK position.
3. Do not disconnect the headlamp switch from its connector.
4. Probe the voltage supply circuit of the interior lamps dimming switch connector with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 3

Go to Step 6

3 |

1. Disconnect the headlamp switch connector.
2. Probe the ground supply circuit of the interior lamps dimming switch connector with a test lamp that is connected to B+.

Does the test lamp illuminate?

Go to Step 4

Go to Step 5

4 | Probe the interior lamps dimming control circuit of the interior lamps dimming switch connector with a test lamp that is connected to a good ground. Does the test lamp illuminate? | Go to Step 7 | Go to Step 8
5 | Repair the open or high resistance in the ground circuit of the interior dimming switch . Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 9 | --
6 | Repair the open or high resistance in the voltage supply circuit of the interior dimming switch . Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 9 | --
7 | Repair the short to ground in the interior lamps dimming control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 9 | --
8 | Replace the headlamp switch. Refer to Headlamp Switch Replacement . Did you complete the repair? | Go to Step 9 | --
9 |

1. Connect all connectors and components that were previously disconnected.
2. Verify that the interior lamps dim properly.

Do the interior lamps dim properly?

System OK

Go to Step 2