1993 Dodge Shadow No Heat in 93 Dodge Shadow

Heater problem
1993 Dodge Shadow 4 cyl Automatic

Not sure what's going on with my usually reliable back-up car. Problem is no heat. We've bled the air out of the radiator, did a system flush, the thermostat is good, it has plenty of anti-freeze, the blower works great, which leaves me wondering why I have no heat.

If you put your hand right over the vents you can feel a little warm air, but no matter how long you let the car warm up, it never warms up! The windows will defrost after about 20 minutes, but you can forget about being even a tiny bit warm. We were told by that it's very rare for the heater core to actually quit working, so I'm starting to wonder if we are in that small percentage.

The only other thing I can think of is that the water pump is not working properly. Water doesn't come out the hoses at a steady pace, just more of a trickle. The car never overheats, but perhaps it's not getting enough water running through for the heater? I just don't know. Please help, because we have been having temps in the teens and my heiney is freezing in that car!