Measure the resistance between connector (3AG) terminals in the test harness AG.
Connector & terminal
(3AG) No. 1 — (3AG) No. 3:
(3AG) No. 3 — Chassis ground:
(3AG) No. 1 — Chassis ground:
Is the resistance 1 MΩ or more?
Replace the airbag main harness along with body harness.