sounds like either a blend door issue, or your actual climate control (in the dash, where your temp is displayed) is on the fritz.
if your problem was with the HVAC control module like I had (handles the electric to vacuum system) your heat would constantly come out the defroster vents; it'* the default setting when the internals get junked.
if your problem was with a heater core or something physical like that; you'd smell antifreeze, lose coolant, and/or have no heat.
i think you need to scavenge car-part.com, to find a new dash bezel (it'* pretty easy to remove/replace, just make sure you un-bolt your wood trim from inside the glove box - the rest of it un-clips but it'* easily bent so be careful. only 2 screws holding your guage bezel on, you have to be careful and un-plug the headlight switch, and old climate contro, and gently work it out of there.