What is the problem with the following sentence? He want to give me a bright red car

In order for the sentence to be correct, want would need to be wants.

"He wants to give me a bright, red car."

He is reffering to one person.

You could also change the sentence to, "They want to give me a bright, red car."

As you can see, you also need a comma between bright and red.

That there should be a "s" at the end of want to make the sentence make sense