Try this procedure.
DISARMING THE SYSTEM
Disconnect the negative battery cable from the battery.
Disconnect the positive battery cable from the battery.
Wait one minute. This time is required for the back-up power supply in the air bag diagnostic monitor to completely drain. The system is now disarmed.
If you are disarming the system with the intent of testing the system, do not! The SRS is a sensitive, complex system and should only be tested or serviced by a qualified automotive technician. Also, specific tools are needed for SRS testing.
ARMING THE SYSTEM
Connect the positive battery cable.
Connect the negative battery cable.
Stand outside the vehicle and carefully turn the ignition to the RUN position. Be sure that no part of your body is in front of the air bag module on the steering wheel, to prevent injury in case of an accidental air bag deployment.
Ensure the air bag indicator light turns off after approximately 6 seconds. If the light does not illuminate at all, does not turn off, or starts to flash, have the system tested by a qualified automotive technician. If the light does turn off after 6 seconds and does not flash, the SRS is working properly.