Chart B

Chart B:

SIR Wiring Diagram:

DESCRIPTION:

When the ignition switch is first turned "ON", system voltage is applied from fuse #15 to "SIR Indicator High", terminal B9 and to the "INFL REST" warning lamp which is connected to "SIR Indicator Low", terminal A1. Fuse #12 applies system voltage to the "Ignition 1" inputs, terminals A3 and B3. The DERM responds by flashing the "INFL REST" warning lamp 7 to 9 times.

When the engine is being cranked, system voltage is applied from fuse #11 to the DERM at the "Crank" input. 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" warning lamp being "ON" during cranking.

After cranking the DERM will again flash the "INFL REST" warning lamp 7 to 9 times.

TEST DESCRIPTION: Number(s) below refer to circled number(s) on the diagnostic chart.

1. An open fuse #12 would result in a loss of "Ignition 1" voltage to the DERM. The DERM will respond by grounding the "SIR Indicator Low", CKT 358 whenever the ignition switch is "ON".

2. A disconnected DERM harness connector will cause the "INFL REST" lamp to come on steady via the shorting bar from terminal A1 to terminal B1.

3. This test checks whether a short to ground caused fuse #12 to open.

4. This test checks for a short from the "SIR Indicator Low" circuit to ground.

5. This test determines whether the short to ground is due to a faulty dual sensor or a short in the wiring.

6. This test checks for an open in the "Ignition 1" circuitry to the DERM.

7. This test checks for a short from the "Crank" input circuit to B+.