The new chairman of the Statue of Liberty/Ellis Island Centennial Commission vowed yesterday to work "in harmony" with his ousted predecessor, Chrysler Corp. Chairman Lee Iacocca, in deciding how to renovate the 23-acre island that was the nation's immigration center for more than half a century.

"To achieve our goals and to avoid any further problems, I said we must continue to work in harmony -- singing off the same sheet of music," Wisconsin banker Armen Avedisian told the panel, which was meeting for the first time since Interior Secretary Donald Hodel fired Iacocca last month. "Lee agreed wholeheartedly."

And so, it appeared, did the commission members, who listened impassively to several proposals for renovating Ellis Island, including a conference center and hotel plan endorsed by the National Park Service that Iacocca had labeled "gross commercialization."

The Immigration and Naturalization Service weighed in with a plan to add educational facilities and a genealogical research center.

Slides provided the only fireworks at yesterday's meeting, as David Wolper, chairman of the Statue of Liberty celebration committee, described plans for a nationally televised four-day extravaganza in July to present the renovated statue.

This $8 million party is to be launched July 3 by President Reagan aboard the aircraft carrier USS John F. Kennedy in New York Harbor, with more than 3,000 paying guests, 3,000 journalists, a 100-piece orchestra and a 1,000-voice choir.

When Reagan flicks a switch, a beam of light will cross the harbor, slowly steal up the statue amid a swell of music, and finally illuminate Miss Liberty's face as the choir bursts into song. "It's going to be quite a moving moment," Wolper said.

Chief Justice Warren E. Burger will swear in 1,500 new citizens on Ellis Island, and 40,000 others will take the oath simultaneously in ceremonies across the nation.

For the grand finale, the statue's torch is to be lit amid spectacular fireworks and booming cannon, a procession of tall ships passing in review, 40,000 boats of all sizes and shapes flashing their lights in the harbor, and possibly 5 million people cheering from shore.

And that, as Wolper said, is just the first day.

Events for the next three days include a day-long parade of tall ships saluted by fireworks in their national colors; concerts by such performers as the Boston Pops Orchestra, Marilyn Horne, Placido Domingo, Johnny Cash and Barry Manilow; a salute by sports stars ranging from Olympic gymnast Mary Lou Retton to the Harlem Globetrotters, and a final bash at the New Jersey Meadowlands studded with Hollywood stars.

Wolper said the celebration would not use money raised for the renovation of the historic landmarks, but would be financed by the sale of television rights and tickets to the opening and closing ceremonies.