President-elect Ronald Reagan, emerging briefly from the seclusion of his Pacific Palisades home to attend church today, said he has been "thinking about" holding an economic summit-meeting with auto industry leaders as soon as he takes office, but has not yet scheduled any such meeting.

United Auto Workers President Douglas Fraser and other UAW leaders Saturday issued a call for such a meeting, saying that the nation "faces the literal collapse of one of its most crucial industries" if current economic: conditions continue.

Reagan, asked by reporters if he would agree to such a session on the auto industry as soon as he took office, replied, "I've been thinking about that one. I haven't made any schedule on it yet."

Reagan also said in response to questions from reporters that he would be "very happy" to meet with Fraser to discuss the problems of the troubled American auto industry.

Reagan, who in recent days has rarely ventured from his home, where aides say he is working on Cabinet selections and his inaugural address, declined to comment on the latest presentation of the Iranian conditions for the release of the 52 American hostages.

Wearing a blue blazer and apearing relaxed and vigorous, Reagan said, "Merry Christmas!" and waved at a cheering crowd of churchgoers when his motorcade pulled up at the Bel Air Presbyterian Church.

Inside, he and his wife, Nancy, sat inconspicuously toward the rear of the packed church as the Rev. Donn D. Moomaw preached a sermon on the meaning of God's word, without any mention of Reagan or politics.

Later, shouting reporters causes the president-elect to pause just before climbing back into his black limousine. Asked about further Cabinet selections, Reagan said, "There'll be some announcements this week, but listen, I'm holding up all those people in the church -- they won't let'em out" [until the motorcade leaves]. Asked if the entire Cabinet would be named by Christmas, he said he didn't know, but "we're going to come close."

An undisclosed number of Cabinet appointments will be unveiled Monday in Washington, and a spokesman at the transition office said nominees were expected to be on hand for the announcement.

If that is the case, the nominee for education secretary either won't be announced or the woman who has appeared almost by default the leading contender did not get the job. Barbara Thompson, Wisconsin superintendent for public education, contacted at home today, said she heard nothing from Reagan or his advisers over the weekend and was busy addressing Christmas cards. Elizabeth Dole, a top transition official mentioned for the education job, was named a presidential assistant Saturday, and Marva Collins, a Chicago educator, removed her name from consideration.

Illinois farm official John R. Block, who is reportedly the choice for agriculture secretary, will be in Washington Monday, according to one of his principal supporters, Sen. Bob Dole (R-Kan.).

Other nominations believed to have been decided by Reagan that might be announced at the afternoon news conference are former South Carolina governor James Edwards as energy secretary, Denver attorney James G. Watt as interior secretary, New York lawyer Samuel Pierce Jr. as secretary of housing and urban development, and Georgetown University professor Jeane Kirkpatrick as U.S. ambassador to the United Nations.

In a Newsweek magazine interview published today, Reagan defends his choice of Alexander M. Haig Jr. for secretary of state, and said, "I expect him to be confirmed." Reagan said he believes the nomination "sends a message of hope to our allies."

Tonight the Reagans attended a reception in their honor at the exclusive Riviera Country Club down the hill from their home.

"I want you to know this is a time of mixed emotions for Nancy and myself," the president-elect told the throng of cheering and well-to-do neighbors and friends. He said he didn't think any president had been elected "from a place as hard to leave as California. . . . Nancy and I have been very happy here."

Laughing with his audience, Reagan quoted letters about the presidency written by small children and published in a newspaper. One, he said, wrote "I should be happy that I am only president and not God." In another, a girl told him, "'Now go to the Oval Office and get to work.'"