Cannot stop the Heat

[P91473]

I recently purchased a 914 (74 1.8) for my 14 year old with the intent to restore in the next two years. It's a running project, runs great as a matter of fact. One issue I would like to correct is the heater; I cannot get it to turn off. Heat comes out even though the dash lever is all the way to the left and the floor lever is down.
A few things I have checked. The heater Blower works as designed: only turning on when the floor lever is up. I removed the driver side heater box and it seems to make a good seal when closed. I verified it opens when the floor lever is up and closes when down. I have not checked the passenger side as are they independent, right? Meaning the right side feeds the right vents (lower and upper) and vise versus. Any thoughts on what I need to check next? Thanks John

[Dave at Pelican Parts]

Make sure that the cable isn't pulling either flapper valve open. Verify that the flaps inside the valves haven't failed, and are actually directing the air to the right place. You can pull the big hose off the flapper to check; the warm air from the exchanger should be dumped out of the "bell" on the side of the valve when the lever on the valve is not pulled closed.

--DD