GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1999 🢒 Astro - 2WD 🢒 Restraints 🢒 SIR 🢒 AIR BAG Warning Lamp Does Not Come On

Object Number: 388354 Size: SF
SIR Components
SIR Schematics
Handling ESD Sensitive Parts Notice
SIR Caution
Handling ESD Sensitive Parts Notice
SIR Schematics

Circuit Description

When the ignition switch is first turned to RUN, the GAUGES Fuse applies battery voltage to the AIR BAG warning lamp that is connected to Air Bag Indicator Control, terminal 7. The AIR BAG Fuse applies battery voltage to the IGNITION 1 input, terminal 10. The inflatable restraint sensing and diagnostic module (SDM) responds by flashing the AIR BAG warning lamp 7 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 power feed circuitry.

    2.

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

    3.

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

    4.

  4. This test determines if the malfunction is in the instrument cluster connector.

    5.

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

    6.

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

    7.

  7. This test inspects whether power is available to the instrument cluster power feed circuit.

    8.

  8. This test inspects for a short from the instrument cluster power feed circuit to ground.

    9.

  9. This test determines whether the short to ground is due to a short in the wiring or internal to the instrument cluster.

    10.

  10. This test determines if the malfunction is in the instrument cluster connector.

    11.

  11. This test determines whether the malfunction is due to an open power feed circuit from the GAUGES Fuse.

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
  1. Set the parking brake.
  2. Turn the ignition switch 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 behind the instrument panel extension.
  3. Disconnect the inflatable restraint sensing and diagnostic module (SDM). Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
  4. Install the J 38715-96 SIR Shorting Bar Tool to the SDM harness connector.
  5. Install the 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. 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.

Is the repair complete?

--

Go to Step 24

--

6
  1. Turn the ignition switch to the OFF position.
  2. Remove the instrument cluster. Refer to Instrument Cluster Replacement in Instrument Cluster, Panel, Gauges and Console.
  3. Inspect for proper connection to the instrument cluster at terminal B17.

Is the connector damaged or corroded?

--

Go to Step 7

Go to Step 8

7

Repair the instrument cluster harness connector. Refer to Connector Repairs .

Is the repair 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. Refer to AIR BAG Indicator Replacement .
  2. Install the instrument cluster.

Is the repair complete?

--

Go to Step 24

--

10
  1. Install the AIR BAG warning lamp bulb.
  2. Measure the resistance from the instrument cluster harness connector terminal A16 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.

Is the repair complete?

--

Go to Step 24

--

12

Service the instrument cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gauges and Console.

Is the repair complete?

--

Go to Step 24

--

13
  1. Turn the ignition switch to the OFF position.
  2. Remove the GAUGES Fuse.
  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 GAUGES Fuse.
  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 behind the instrument panel extension.
  2. Disconnect the instrument cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gauges and Console.
  3. Replace the GAUGES Fuse.
  4. Turn the ignition switch to the RUN position for 10 seconds.
  5. Turn the ignition switch to the OFF position.
  6. Remove the GAUGES Fuse.
  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.
  2. Replace the GAUGES Fuse.

Is the repair complete?

--

Go to Step 24

--

17
  1. Service the instrument cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gauges and Console.
  2. Install the GAUGES Fuse.

Is the repair complete?

--

Go to Step 24

--

18

Install the GAUGES Fuse.

Is the repair complete?

--

Go to Step 24

--

19
  1. Remove the instrument cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gauges and Console.
  2. Inspect for proper connection to the instrument cluster at terminal B17.

Is the connector damaged or corroded?

--

Go to Step 20

Go to Step 21

20

Repair the instrument cluster harness connector. Refer to Connector Repairs .

Is the repair complete?

--

Go to Step 24

--

21

Measure the resistance between the instrument cluster harness connector terminal B17 to each terminal of the GAUGES Fuse 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 GAUGES Fuse.

Is the repair complete?

--

Go to Step 24

--

23
  1. Repair an open condition in the power feed to the GAUGES Fuse.
  2. Install the GAUGES Fuse.

Is the repair complete?

--

Go to Step 24

--

24
  1. Reconnect all the SIR system components.
  2. Ensure that all of the components are properly mounted.

Have all the SIR components been reconnected and properly mounted?

--

Go to SIR Diagnostic System Check

--