Chart B-1

Chart B1:

DERM Circuit Detail:

DESCRIPTION:

When the Ignition Switch is first turned "ON" system voltage is applied through fuse #15 to "SIR Indicator High" (B9) and to the "INFLATABLE RESTRAINT" Indicator Lamp which is connected to "SIR Indicator Low" (A1). Fuse #12 also applies system voltage to the "IGNITION 1" inputs (A3 and B3). The DERM responds by blinking the "INFLATABLE RESTRAINT" indicator 7 to 9 times.

The purpose of the Shorting Bar is to turn the "INFLATABLE RESTRAINT" Indicator Lamp ON should the DERM become disconnected.

When the engine is being cranked system voltage is applied to the DERM at the "CRANK" input. The DERM grounds the lamp circuit until system voltage is removed from the "CRANK" input. This results in a steady "INFLATABLE RESTRAINT" indicator during cranking.

After cranking the DERM will again blink the "INFLATABLE RESTRAINT" indicator 7 to 9 times.

NOTES ON FAULT TREE:

1. An open SIR fuse would result in a loss of "IGNITION 1" voltage at the DERM. The DERM will respond by grounding the lamp circuit ("SIR Indicator Low") whenever the Ignition Switch is "ON"

2. Checks for a short to ground in the "IGNITION 1" circuits or the DERM.

3. Checks if short to ground is in the DERM or the "IGNITION 1" circuits.

4. If the DERM and the SIR harness connector are disconnected the shorting bar between terminals A1 and B1 of the harness connector will ground the lamp circuit.

5. Checks for short in the DERM wiring harness.

6. Checks for short to voltage in the "CRANK" circuit.