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

Object Number: 389962 Size: MF
Cell 10: ILLUM, PARK LP Fuses
Cell 10: TURN, SIR and GAUGES Fuses
Cell 10: TURN, SIR and GAUGES Fuses
Cell 51: Power and Ground
SIR Components
Cell 47: IP Module Switch
SIR Handling Caution
Handling ESD Sensitive Parts Notice
SIR Schematic Icons
Cell 14: G203 and G204 (Pickup)
Handling ESD Sensitive Parts Notice
Cell 14: G203 and G204 (Pickup)

Circuit Description

When the ignition switch is first turned to the RUN position, the GAUGES Fuse applies battery voltage to the AIR BAG warning lamp that is connected to Air Bag Indicator Control, terminal 7. The SIR 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 lap 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 instrument cluster or an open in the warning lamp circuitry.

    6.

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

    7.

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

    8.

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

    9.

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

    10.

  10. 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 light?

--

Go to Step 3

Go to Step 11

3
  1. Turn the ignition switch to the OFF position.
  2. Disconnect the inflatable restraint steering wheel yellow 2-way connector at the base of the steering column and the IP module yellow 2-way connector located behind the glove box.
  3. Disconnect the 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 22

--

6
  1. Turn the ignition switch to the OFF position.
  2. Remove the instrument cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gauges and Console.
  3. Inspect for proper connection to the instrument cluster at terminal B12.

Is the connector damaged or corroded?

--

Go to Step 7

Go to Step 8

7

Repair the instrument cluster harness connector. Refer to Wiring Repair .

Is the repair complete?

--

Go to Step 22

--

8

Using the J 39200 Digital Multimeter (DMM) measure the resistance from the instrument cluster harness connector terminal B12 to the SDM harness connector terminal 7.

Is the resistance within the specified values?

0-5 ohms

Go to Step 10

Go to Step 9

9
  1. Repair an open condition in CKT 358.
  2. Install the instrument cluster.

Is the repair complete?

--

Go to Step 22

--

10

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

Is the repair complete?

--

Go to Step 22

--

11
  1. Turn the ignition switch to the OFF position.
  2. Remove the GAUGES Fuse.
  3. Inspect the GAUGES fuse.

Is the fuse good?

--

Go to Step 17

Go to Step 12

12
  1. Replace the GAUGES 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 16

Go to Step 13

13
  1. Disconnect the inflatable restraint steering wheel yellow 2-way connector at the base of the steering column and the IP module yellow 2-way connector located behind the glove box.
  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 15

Go to Step 14

14
  1. Repair a short to ground condition in CKT 39.
  2. Replace the GAUGES Fuse.

Is the repair complete?

--

Go to Step 22

--

15
  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 22

--

16

Install the GAUGES Fuse.

Is the repair complete?

--

Go to Step 22

--

17
  1. Remove the instrument cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gauges and Console.
  2. Inspect for proper Ignition feed circuit connection to the instrument cluster.

Is the connector damaged or corroded?

--

Go to Step 18

Go to Step 19

18

Repair the instrument cluster harness connector. Refer to Wiring Repair .

Is the repair complete?

--

Go to Step 22

--

19

Measure the resistance between the instrument cluster harness connector Ignition feed circuit to each terminal of the GAUGES Fuse fuseholder.

Is either reading within the specified values?

0-5 ohms

Go to Step 21

Go to Step 20

20
  1. Repair an open condition in CKT 39.
  2. Install the GAUGES Fuse.

Is the repair complete?

--

Go to Step 22

--

21
  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 22

--

22
  1. Reconnect all of the SIR system components.
  2. Ensure that all of the components are properly mounted.

Have all of the SIR components been reconnected and properly mounted?

--

Go to SIR Diagnostic System Check

--