To Undecided Voters, Harris Is Famous, but Unknown. They Want to Learn More.

Teri York-Singleton is certain about one thing as she considers the November election: She will not vote for Donald J. Trump.

Ms. York-Singleton, who runs a nonprofit outside Detroit, grew up in a Democratic household but considers herself more of a political independent. And while she finds Vice President Kamala Harris’s sudden entry in the presidential race refreshing, Ms. Harris has not closed the sale for her.

“I need more information from her,” said Ms. York-Singleton, 68. She listed the costs of medication and child care as well as homelessness as problems she wants to hear Ms. Harris discuss. “People are working two to four jobs just to afford rent,” she added.

There is no doubt that Ms. Harris has lit a fire inside the Democratic Party. She is drawing tens of thousands of fans to her rallies and raising hundreds of millions of dollars. A poll released last week by the Pew Research Center found that Ms. Harris has erased the enthusiasm gap between Democrats and Republicans: 62 percent of Harris voters now say they strongly support her, compared with 43 percent of Biden voters who expressed strong support for him in July. Among former President Trump’s supporters, 64 percent characterized their backing for him as strong.

But even to many voters who lean toward the Democratic ticket, the vice president remains largely undefined. And they are not as enamored with her as those flocking to see her speak.

“She’s famous, but she’s unknown,” said Cornell Belcher, a Democratic strategist and pollster.