Should fans always run with ac on?

1998 Dodge Grand Caravan Sport, AC still works fine but I notice that the fans do not automatically come on when I tune the ac on. They do both come on when it reach's a certain temp but I've heard some say that one of the fans should automatically come on when the ac is turned on. Not sure if that is a symptom of a relay going bad or just they way these are intended to work.

They other thing about the AC is, even though the AC is still blowing cold, I don't see any puddles of water on the ground after running it for awhile, I suspect the drain tube might be plugged and should be cleaned out but I can't seem to find it after crawling under it.

Thanks for any help,

Yes, once the pressures in the A/C system have built up, the fans should turn on. That should happen within seconds of you pushing the A/C switch.

You may or may not see a "puddle" depending on the ambient humidity and temp. The drain tube is on the passenger side and about the middle of the firewall. Here's a pic: http://forum.chryslerminivan.net/attachment.php?attachmentid=486&d=1181523984 You may not have the elbow pictured. Could be just a small tube sticking 1/2 inch out of the firewall.