Not much to go on, Ralph.

Is the engine getting up to temp? If you can lay a hand on the engine after a
30-minute drive, you may need a new thermostat.

How does water get into the cabin where the heater core is?  Probably two heater
hoses, one of which typically has a valve. If that valve is not opening, or just
opening a little, you have a problem.  If working correctly, you should have a
hot hose between valve and firewal, and a warm return hose.  If the return is
cold, the valve may be the problem. Or maybe whatever opens it (vacuum) is lost.
Is a vac hose disconnected or broken?

If there's plenty of heat as above, the last thing is the air mixer in the
plenum under the dash. There is usually a door that regulates between hot and
cold air to give you the mix required. It's probalby operated by a vacuum motor.
The motor can be broken, or not getting vacuum. Could be the vacuum switching
mechanism is faulty.  Stick your head under the dash, with a flashlight, and
work the heater controls from cold to hot, and see if there is any activity.

That's pretty general stuff, and your Chrysler may do things differently.

Texas Parts Guy