Chart D "Air Bag" Warning Lamp Does Not Come "on"

CIRCUIT DESCRIPTION
When the ignition switch is first turned to "ON," system voltage is applied from Fuse C-22 to the DERM at the "SIR Indicator High" input, terminal "B9," and to the "INFL REST" indicator (located in the instrument cluster) which is connected to the "SIR Indicator Low," terminal "A1." Fuse 0-23 applies system voltage to the "Ignition 1" input, terminals "A3" and "B3." The DERM responds by flashing the "INFL REST" indicator 7 to 9 times.

When the engine is being cranked, system voltage is applied from Fuse C-21 to the DERM and the "Crank" input, terminal "B10." The DERM responds by grounding the "SIR Indicator Low" output until system voltage is removed from the "Crank" input. This results in the "INFL REST" indicator being illuminated steady during cranking.

After cranking, the DERM will again flash the "INFL REST" indicator 7 to 9 times.

TEST DESCRIPTION:
Number(s) below refer to circled number(s) on the diagnostic chart.
1. This test checks to see if the fault is in the power feed to the instrument cluster.
2. This test checks the integrity of the "SIR Indicator High" CKTs 39C and 39D.
3. This test determines whether the open is in the "SIR Indicator High" CKTs 39C and 39D or in the instrument cluster.
4. This test checks for an open in the "SIR Indicator Low" CKT 358, instrument cluster or "INFL REST" indicator bulb.
5. This test checks to see if the fault is due to an open "INFL REST" indicator bulb.
6. This test checks for a good ground to the SIR system.
7. This test determines whether the fault is a short to B+ in the "SIR Indicator Low" CKT 358 or a faulty DERM.
8. This test determines whether the open is in the "SIR Indicator Low" CKT 358 or in the instrument cluster.
9. This test checks to see if power is available to the instrument cluster power feed CKTs 39A and 39B.
10. This test checks to see if the fault is due to an open Fuse C-22.
11. This test determines whether the open Fuse C-22 is due to a short to ground in the instrument cluster power feed CKTs 39A and 3913 or a faulty DERM.
12. This test determines whether the fault is due to an open in the instrument cluster power feed CKTs 39A and 3913 or an open in the power feed to Fuse C-22