I have a 98 Venture and I have noticed that it will lock itself sometimes when I get out and leave it running. Temperature not a factor. A friend has a 2000 Venture and he carries an extra set of keys in case he gets locked out AGAIN!! An auto start is handy for this as once you stop somewhere and want to leave it running, press the button and take keys with you . As for the airbag light, check with mechanic or have your comp. codes checked. Never had that yet!!
Kevin