Why does a 1994 Ford Areostar mini van just make a clicking sound when you try to turn it on?

If it does not start and just makes a clicking sound, this is an indication of: a low battery, poor battery connections, or a defective starter solenoid ( next to the battery hooked up by the short positive battery cable). Check and clean your battery cables first , then look to the solenoid if you know the battery is fully charged. I hope this helps you. Mark