Chart A-3

Chart A3:

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" (A1). Fuse #12 also applies system voltage "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 wiring shorts between 36VLR (CKT 236) and CKTs 347A, 347B, 348A, 348B and 349 of the SIR wiring harness. Also checks for intermittent open in CKT 348A.

2. Checks for intermittent opens in the 36VLR wiring (CKT 236).

3. Checks for intermittent open between fuse #12 and the arming sensor (CKT 1139).