The outside temp sensor works with the fresh air front flap. When the outside temperature exceeds inside temperatures, it closes and vise versa depending on how you have the temperature dial set.

A good check if the pod is broken is to drive on the freeway and feel if there is air coming through the vents with the CCU set of OFF. When OFF, there should be no air coming through. I know this because I replaced my pods on my 260E and it does not blow any air through....my 300TE OTOH does and it is quite irritating on a cold day because then you have to close the vents completely. Also it does not help when it is hot outside since it is not closing.

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