Air Bag Control Module: Description and Operation

AIR BAG CONTROL MODULE (ACM)
The ACM/Air Bag System Diagnostic Module (ASDM) contains safing sensor and energy reserve capacitor, while the ACM/Air Bag Electronic Control Module (AECM) contains impact sensor and energy reserve capacitor. The ACM monitors system to determine system readiness. The ACM will store sufficient energy to deploy air bag for two minutes after battery has been disconnected. The ACM contains an on board diagnostics function that will illuminate air bag warning lamp when a system fault occurs.

NOTE: The following information is intended to be used in conjunction with the electrical diagrams.

CIRCUIT OPERATION
Two circuits provide battery voltage to the Airbag Control Module (ACM), F14 and F20. Circuits F14 and F20 are connected to separate bus bars in the fuse block. Different circuits from the Power Distribution Center (PDC) and the ignition switch supply battery voltage to the fuse block bus bars.

Circuit F20 supplies battery voltage to the ACM only when the ignition switch is in the RUN position. Circuit F14 circuit powers the ACM when the ignition switch is in either the START or RUN position.

In either the START or RUN positions, the ignition switch connects circuit A21 circuit with circuit A1 from fuse C in the PDC. Circuit A21 circuit supplies battery voltage to the fuse block bus bar that feeds circuit F14. Fuse 14 in the fuse block protects circuit F14. Circuit F14 connects to cavity 1 of the ACM.

When the ignition switch is in the RUN position, it connects circuit A2 from fuse E in the PDC to circuit A22. Circuit A22 supplies battery voltage to the fuse block bus bar that feeds circuit F20. Fuse 3 in the fuse block protects circuit F20. Circuit F20 connects to cavity 2 of the ACM.

The ACM is case grounded and has an external dedicated ground, circuit Z6. Circuit Z6 connects to the right fender side shield.