I have a 1999 ford F150 and just recently I took my key to turn my passenger air bag off and my air bag service light came on and know it want go off when you turn the airbag back to the on position.Any body have any idea what might be wrong with my system.

I had a 98 GMC Sonama that did that.All that is,is that's it's telling you that the passenger airbag is off.It's like a reminder.So that way when you have a passenger and you wantr them to feel safe you can turn it on.