another new one sort of

[Dean and buster]

ok have had the craziest thing happen on my 07 e350 I was on the interstate and stepped on the gas to pass some one and the ac went up to the defroster vent so I think I found a remedy for this there is a vacuum box that has to be by passed I found this out from the dealer today   so they told me how to fix it I will let you know tomorrow  if it works other wise it is a 10 hour job at the shop