Chart B-2

Chart B2:

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. Checks if there is a short to ground on the low side of the lamp circuit external of the DERM. The SIR Load Tool prevents the shorting bar in the DERM connector from grounding the lamp circuit.

2. Checks for "IGNITION 1- voltage at the DERM. If the "IGNITION 1" circuits are open the DERM will ground the lamp circuit whenever the Ignition Switch is "ON" (if the "SIR Indicator High" circuit is good).

3. Checks for a short to system voltage in the "Crank" circuit.