No or very little heat

I have a 97 dakota, 3.9L gives off very little heat. Engine temp reads around 190 / 200 degrees. Had the same problem in a '93 dakota, never could figure out what was wrong. New thermostat, flushed the heater core. Still no heat. Engine temp never got above 130 / 140 in the winter. I would do a bad thing and cover 90 percent of the radiator to get any kind of heat from it.

Now my 97 has the same problem. Also when I sit at a light, the temp my drop and I get even less heat.

Frank

Low water, or heater temperature control knob stuck on cool but you can't tell.