4 seasons heater/ac dash control

[willy12844]

I had to pull this control to replace a broken lever, I noticed on the top left side in the back is a 3 port valve that has one port blocked and no hoses connected to the other 2 ports. This valve is activated by movement of the top lever and by the middle lever when moved to the far right to heater. the ports look like they accommodate 1/8" ID hose, there were no hoses connected to it.
Can someone tell me what it is and what I need to do with it?

Thank You,
Bill












































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