Heat works on passenger side but blows cold on driver side. on 2004 Toyota Sienna

We have a 2004 toyota sienna xle AWD and the heat only blows hot on the passenger side. The ac blows cold as ice on both sides and in the back. But when we turn the heat on it just blows cold air on the drivers side front. We are clueless!!

Asked by for the 2004 Toyota Sienna