It gets cold when your heater doesn't put out heat

Here's the story:
i have a 1992 ranger that doesnt seem to want to put out any heat. i have replaced the water pump, thermostat, upper and lower radiator hoses. It is almost like the coolant isnt getting hot enough because when i have the blower on low it will blow some heat but when i turn it up, it gets cold. also the temperature gauge on the dash stays very close to cold no matter how long the engine has been running. I live in Ohio and it gets pretty cold up here in the winter and i would love to have some heat in my turck. any ideas?

Looking through my manual, I came up with a possibility that the problem might be in the heater core where hot engine coolant may not be getting in there, keeping hot air from getting into the compartment. The core is located under the dashboard. It's just a guess, but I hope it helps out. Good luck.

Actually i figured it out, simple. one of the heater core lines was too worn out and it was collapsing, restricting the collant flow. i get heat that feels like the pitts of hell!! ;) thanks for the help anyways. happy holidays!