I have almost the same problem than Peter, here: Entity reference view depending on other field
I have a contact form with two fields: brand and model. Brand is a taxonomy field and Model en entity reference view field. Model field (autocomplete) should be dependent on brand value: nothing if brand is not selected or only products with the brand field chosen.
I think @Francis Yaconiello gave the right answer but I don't understand the relations and contextual filter in his view. If you see this, Francis, can you help me?