For 1990-2009 cars
SIR Schematics
SIR Components
SIR Caution
Handling ESD Sensitive Parts Notice

### Circuit Description

When the ignition switch is first turned to RUN, the IGN 1 Fuse (Buick), CHIME Fuse (Oldsmobile) applies battery voltage to the AIR BAG warning lamp that is connected to SIR INDICATOR, terminal 7. The AIR BAG Fuse applies battery voltage to the IGNITION POSITIVE VOLTAGE input, terminal 10. The inflatable restraint Sensing and Diagnostic Module (SDM) responds by flashing the AIR BAG warning lamp seven times.

When measurements are requested in this table, use the J 39200 DMM with the correct terminal adapter from the J 35616 Connector Test Adapter Kit. When an inspection for proper connection is requested, refer to Testing for Electrical Intermittents in Wiring Systems. When a wire, connector or terminal repair is requested, use the J-38125 Terminal Repair Kit and refer to Wiring Repairs in Wiring Systems.

### Test Description

The numbers below refer to the step numbers on the diagnostic table:

1. This test determines whether the malfunction is in the inflatable restraint Sensing and Diagnostic Module (SDM) circuitry or in the instrument cluster (Buick), remote indicator bank (Oldsmobile) power feed circuitry.

2. This test determines whether voltage is present in the warning lamp circuit.

3. This test isolates CKT 358 and checks for a short in CKT 358 to B+.

4. This test determines if the malfunction is in the instrument cluster (Buick), remote indicator bank (Oldsmobile) connector.

5. This test determines if the open is due to a bad bulb.

6. This test isolates an open in the warning lamp circuitry.

7. This test checks whether power is available to the instrument cluster (Buick), remote indicator bank (Oldsmobile) power feed circuit.

8. This test checks for a short from the instrument cluster (Buick), remote indicator bank (Oldsmobile) power feed circuit to ground.

9. This test determines whether the short-to-ground is due to a short in the wiring or internal to the instrument cluster (Buick), remote indicator bank (Oldsmobile).

10. This test determines if the malfunction is in the instrument cluster (Buick), remote indicator bank (Oldsmobile) connector.

11. This test determines whether the malfunction is due to an open power feed circuit from the IGN 1 Fuse (Buick), CHIME Fuse (Oldsmobile).

#### Air Bag Warning Lamp Does Not Come On

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the SIR Diagnostic System Check performed? | -- | Go to Step 2 | Go to SIR Diagnostic System Check
2 | Note the instrument cluster (Buick), remote indicator bank (Oldsmobile) while the ignition switch is turned to the RUN position. Does the BRAKE indicator illuminate? | -- | Go to Step 3 | Go to Step 13
3 |

1. Turn the ignition switch to the OFF position.
2. Disconnect the inflatable restraint steering wheel and IP module yellow 2-way connectors at the base of the steering column and above the right sound insulator.
3. Disconnect the inflatable restraint Sensing and Diagnostic Module (SDM).
4. Install J 38715-96 SIR Shorting Bar Tool to the SDM harness connector.
5. Install the Connector Position Assurance (CPA).
6. Turn the ignition switch to the RUN position.
7. Measure the voltage on the SDM harness connector from terminal 7 to ground.

Is the voltage more than the specified value?

10.0 V

Go to Step 4

Go to Step 6

4 |

1. Turn the ignition switch to the OFF position.
2. Disconnect the instrument cluster (Buick), remote indicator bank (Oldsmobile). Refer to Instrument Cluster Replacement in Instrument Panel, Gauges, and Console.
3. Turn the ignition switch to the RUN position.
4. Measure the voltage on the SDM harness connector from terminal 7 to ground.

Is the voltage less than the specified value?

1.0 V

Go to Sensing and Diagnostic Module Integrity Check

Go to Step 5

5 |

1. Turn the ignition switch to the OFF position.
2. Repair a short-to-B+ condition in CKT 358.
3. Reconnect the instrument cluster (Buick), remote indicator bank (Oldsmobile).

Are the repairs complete?

--

Go to Step 24

--

6 |

1. Turn the ignition switch to the OFF position.
2. Remove the instrument cluster (Buick), remote indicator bank (Oldsmobile). Refer to Instrument Cluster Replacement in Instrument Panel, Gauges, and Console.
3. Check for proper connection to the instrument cluster (Buick) terminal E3, remote indicator bank (Oldsmobile) terminal A9.

Is the connector damaged or corroded?

--

Go to Step 7

Go to Step 8

7 | Repair the instrument cluster (Buick), remote indicator bank (Oldsmobile) harness connector. Refer to Connector Repairs in Electrical Diagnosis. Are the repairs complete? | -- | Go to Step 24 | --
8 |

1. Remove the AIR BAG warning lamp bulb. Refer to AIR BAG Indicator Replacement .
2. Inspect the bulb.

Is the bulb good?

--

Go to Step 10

Go to Step 9

9 |

1. Replace the AIR BAG warning lamp bulb.
2. Install the instrument cluster (Buick), remote indicator bank (Oldsmobile).

Are the repairs complete?

--

Go to Step 24

--

10 |

1. Install the AIR BAG warning lamp bulb.
2. Measure the resistance from the instrument cluster (Buick) harness connector terminal E3, or remote indicator bank (Oldsmobile) harness connector terminal A9 to the SDM harness connector terminal 7.

Is the resistance within the specified values?

0-5 ohms

Go to Step 12

Go to Step 11

11 |

1. Repair an open condition in CKT 358.
2. Install the instrument cluster (Buick), remote indicator bank (Oldsmobile).

Are the repairs complete?

--

Go to Step 24

--

12 | Service the instrument cluster (Buick), remote indicator bank (Oldsmobile). Are the repairs complete? | -- | Go to Step 24 | --
13 |

1. Turn the ignition switch to the OFF position.
2. Remove the IGN 1 Fuse (Buick), CHIME Fuse (Oldsmobile).
3. Inspect the fuse.

Is the fuse good?

--

Go to Step 19

Go to Step 14

14 |

1. Replace the fuse.
2. Turn the ignition switch to the RUN position for 10 seconds.
3. Turn the ignition switch to the OFF position.
4. Remove the IGN 1 Fuse (Buick), CHIME Fuse (Oldsmobile).
5. Inspect the fuse.

Is the fuse good?

--

Go to Step 18

Go to Step 15

15 |

1. Disconnect the inflatable restraint steering wheel and IP module yellow 2-way connectors at the base of the steering wheel and above the right sound insulator.
2. Disconnect the instrument cluster (Buick), remote indicator bank (Oldsmobile). Refer to Instrument Cluster Replacement in Instrument Panel, Gauges, and Console.
3. Replace the IGN 1 Fuse (Buick), CHIME Fuse (Oldsmobile).
4. Turn the ignition switch to the RUN position for 10 seconds.
5. Turn the ignition switch to the OFF position.
6. Remove the IGN 1 Fuse (Buick), CHIME Fuse (Oldsmobile).
7. Inspect the fuse.

Is the fuse good?

--

Go to Step 17

Go to Step 16

16 |

1. Repair a short-to-ground condition in CKT 39. Refer to Wiring Repairs in Wiring Systems.
2. Replace the IGN 1 Fuse (Buick), CHIME Fuse (Oldsmobile).

Are the repairs complete?

--

Go to Step 24

--

17 |

1. Service the instrument cluster (Buick), remote indicator bank (Oldsmobile).
2. Install the IGN 1 Fuse (Buick), CHIME Fuse (Oldsmobile).

Are the repairs complete?

--

Go to Step 24

--

18 | Install the IGN 1 Fuse (Buick), CHIME Fuse (Oldsmobile). Are the repairs complete? | -- | Go to Step 24 | --
19 |

1. Remove the instrument cluster (Buick), remote indicator bank (Oldsmobile). Refer to Instrument Cluster Replacement in Instrument Panel, Gauges, and Console.
2. Check for proper connection to the instrument cluster (Buick) at terminals E15 and F15, or the remote indicator bank (Oldsmobile) at terminal A1.

Is the connector damaged or corroded?

--

Go to Step 20

Go to Step 21

20 | Repair the instrument cluster (Buick), remote indicator bank (Oldsmobile) harness connector. Refer to Connector Repairs in Wiring Systems. Are the repairs complete? | -- | Go to Step 24 | --
21 | Measure the resistance between the instrument cluster (Buick) harness connector terminal E15, or the remote indicator bank (Oldsmobile) harness connector terminal A1 to each terminal of the IGN 1 Fuse (Buick), CHIME Fuse (Oldsmobile) fuseholder.

Is either reading within the specified values?

0-5 ohms

Go to Step 23

Go to Step 22

22 |

1. Repair an open condition in CKT 39.
2. Install the IGN 1 Fuse (Buick), CHIME Fuse (Oldsmobile).

Are the repairs complete?

--

Go to Step 24

--

23 |

1. Repair an open condition in the power feed to the IGN 1 Fuse (Buick), CHIME Fuse (Oldsmobile).
2. Install the IGN 1 Fuse (Buick), CHIME Fuse (Oldsmobile).

Are the repairs complete?

--

Go to Step 24

--

24 | Reconnect all the SIR system components, make sure all the components are properly mounted. Have all the SIR components been reconnected and properly mounted? | -- | Go to SIR Diagnostic System Check | --