Take the sentence, "He wants to go on vacation." Is the verb in that sentence "wants" or "wants to go"?

I am going to take a shot at answering this question, please feel free to correct me. The verb has to match the subject.so wants is correct. I believe.

He wants to go on vacation.

He- Subject Noun
wants - verb transitive
to go - direct object (infinitive functioning as a noun, in the role of DO)
on vacation - adverbial phrase (prepositional phrase functioning as an adverb in the sentence answering the question "wants to go where?") (on- preposition, vacation- object of the preposition)

Great answer.

Here's more on infinitive verbs.