Two things.
The heater problem is most likely the heater fan resistor that has rusted and broken. Depending on what van you have it is either under the hood or under the dash. Repost more info (year, make, model & engine) & I can get more specific.
The airbag may also be a number of things. The most popular item for Chrysler is the clockspring failure in the steering column, but I would suggest a scan to identify this problem. It can get real expensive throwing airbag parts at a car.
In the meantime, here is some more information about the clockspring
The clockspring is a ribbon wire that is coiled up inside the steering column. It delivers current to all of the systems mentioned above, airbag, cruise control and horn. When it fails (and they do a lot) the wire breaks leaving the circuit open and inoperative. This will cause the airbag light to come on and shut down the system. As long as that light is on, the airbags will NOT deploy, even in an accident.
This was a factory recall and many customers are unaware of that. Her is that link
Clockspring Recall
Contact your local dealer and they will accommodate the replacement for you.
Check out these web pages for a more complete description:
http://www.airbagsolutions.com/docs/Clockspring.pdf
http://www.airbagsolutions.com