No Heat

I have a 90 Pont Grand Prix and I havent had heat in 2 years and I live in Canada. I have changed the T-stat a number of times and climate control module and still no heat, blead out the system and heater core. I get sum but not alot and its mostly cold air. pls help :( frezin my butt off

I have a 90 Pont Grand Prix and I havent had heat in 2 years and I live in Canada. I have changed the T-stat a number of times and climate control module and still no heat, blead out the system and heater core. I get sum but not alot and its mostly cold air. pls help :( frezin my butt off

Ever check lines to see if one is blocked?

Ever check lines to see if one is blocked?
lines are not blocked everything is working I also swaped the heater core lines and got heat but then after I drove it the heat just faded away and I switched them back. but I heard that one of the vent doors or the motor mite be gone so I was also wondering how to get to the door flaps any idea?