Chart A-2

Chart A2:

DERM Circuit:

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" (Al). 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.

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. Checks for intermittent shorts to system voltage in the 36VLR wiring (CKT 236).

2. Checks for intermittent shorts in the 36VLR wiring (CKT 236) to ground or to DERM supplied ground through the lamp driver.

3. Checks for intermittent open in the 36VLR wiring (CKT 236).

4. Checks for intermittent open in the Force Hi wiring (CKT 714) and for intermittent shorts from Force Low (CKT 688) to Sense Low (CKT 752) or to CKT 348.

5. Checks for intermittent opens or shorts to ground in the Sense Low wiring (CKT 752).

6. Checks for shorts to ground in the deployment loop (CKTs 347 and 348) or shorts to ground in the diagnostic circuits (CKTs 688, 714 and 753). Also checks for intermittent open in CKT 347A.