For 1990-2009 cars

### Circuit Description

The low air indicator illuminates when ground is applied to the low air indicator control circuit.

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Brake Warning System Schematics
1 | Did you review the Brake Warning System Description and Operation and perform the necessary inspections? | Go to Step 2 | Go to Brake Warning System Description and Operation
2 | Verify a fault is present. Does the system operate normally? | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3
3 | Is the low air indicator and the low air pressure warning alarm inoperative? | Go to Step 4 | Go to Step 6
4 |

1. Disconnect the low air pressure switch.
2. Connect a fused jumper wire from the low air indicator control circuit to the ground circuit.
3. Turn ON the ignition.

Does the low air indicator illuminate?

Go to Step 12

Go to Step 5

5 | Connect the fused jumper wire from the low air indicator control circuit to a good ground . Does the low air indicator illuminate? | Go to Step 10 | Go to Step 9
6 |

1. Disconnect the instrument panel cluster.
2. Connect a test lamp from the battery positive voltage circuit to a good ground.

Does the test lamp light?

Go to Step 7

Go to Step 11

7 | Test the low air indicator control circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 8
8 | Replace the instrument panel cluster. Did you complete the replacement? | Go to Step 13 | --
9 | Repair the open in the low air indicator control circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 13 | --
10 | Repair the open in the ground circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 13 | --
11 | Repair the open in the battery positive voltage circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 13 | --
12 | Replace the low air pressure switch. Refer to Low Air Pressure Switch Replacement . Did you complete the replacement? | Go to Step 13 | --
13 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2