One problem related to air bag on-off switch has been reported for the 2004 Toyota 4Runner. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2004 Toyota 4Runner based on all problems reported for the 2004 4Runner.
Driver side and passenger side air bags deployed when ignition switch was turned to first position. Engine was not running and car was in park. My car was parked in my garage at the time air bags exploded and has not been in any accidents.