AC: Left side blows cold, right side blows hot

[DGr1FF]

Hello,

Recently started having an issue with my 2000 C230. Randomly the ac will start blowing hot on the right side (Right vent + right/center vent). It doesn't happen often, but when it does it is very strange. I can try to mess with the fan power or hot/cold settings, and sometimes it self-fixes. Other times I am left to turn the AC off for the remainder of the ride. Does anyone know what this could be? Thanks in advance for any suggestions.

[kowalski]

have you checked duo valves?
they get a hiccup sometimes

[Chisel86]

This happens to me as well. What is a duo valve and how do you get to it?

[kowalski]

duo valve is on the passengers side in the engine bay where the struts are bolted
there are 2 small cups attached to some rubber hoses, these are the duo valves

[DRBC43AMG]

Several duo-valves operate the HEVAC. One apparently is a bitch to remove and needs dismantling the entire dash board.
Diagram of the vacuum operated valves below.

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