If I remember right, the 'default' flow is NOT is not out the front vents. I think the default position of the defrost pod is open, not closed.

Not too hard to check your pods - probably at least some are bad. Check them and then at least you will know. If you have no defrost flow, I think the defrost pod must be good. If I remember right!

I did have a bad manifold once - the part with all the vacuum hoses on it, behind the glove box. I had a bad control unit once, also.

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2012 E350
2006 Callaway SC560