In November of 2017 my father passed away. He left me a vehicle. There was no will.
If he had no will, then what does your statement that he "left [you] a vehicle" mean?
He did leave me a signed and notarized document titled beneficiary designation.
Without being able to read that document or having a clear and accurate summary of what it says, it's impossible to know if this document had any legal effect. That being said, insurance policies and financial accounts typically have beneficiary designations; motor vehicles do not.
Note that I'll defer to "adjusterjack" as it concerns the particular document that he mentioned, if, in fact, it is the same thing that you're talking about.
I was only 17 when my father passed, and they took the vehicle and hid it from me.
Who are "they"?
I want to take them to court over this. Do I have a good case?
The facts you've provided thus far are unclear, so it's impossible to be certain, but probably not.
Since your father died without a will, the disposition of his estate was governed by Arizona's intestate succession laws. Those laws provide that, when a person dies without a will and is survived by a spouse and descendants who are also descendants of the surviving spouse, the surviving spouse inherits the entire net estate (after payment of estate debt). If, by chance, your mother and father were not married at the time of his death, then his net estate (after payment of estate debt) would be divided evenly between his children.
What if I had that form and the title, but my brother did a non probate affidavit prior to me being able to go ahead and file the form and the title?
When and where did he file this affidavit? Your father died a year and a half ago, so you've obviously had plenty of time to act on document you mentioned.