Like thousands of students across the country, John B. Anderson returned to campus today looking for the old magic of springtime.

He found it was there waiting, somewhat apprehensively, like an old but neglected romance ready to be rekindled. The old lines, so seductive last winter and spring, still worked. The old interest was still there.

A crowd that police estimated at 2,000 endured a noontime rain and a wait to greet Anderson at the Universisty of Michigan which does not open classes until Thursday.

Students cheered when he said,"We don't need to register, we don't need a draft" They cheered wildly when said, "We ought to be willing to tax ourselves up to 50 cents a gallon of gasoline."

They nodded appreciatively when he said, "I want to welcome you back to the political process." And they cheered out and long when he said, "I think before we send young men and young women abroad to fight for oil we have to be willing to make maximum efforts toward conservation."

But Anderson's new lines of summer did not hold the same magic. His talk of jobs programs and using tax breaks to fight inflation did not draw the same feverish response. And when his speech began to wander, Anderson was repeatedly interrupted by shouts from the audience for more specifics: "What about foreign policy?" "What about the Mideast?" "What about the Clinch River breeder reactor?"

At several points, the independent presidential candidate shifted gears. Responding to the shouts he urged students to read what his new 317-page platform has to say about energy.

On nuclear power, one of the few issues to create protests on campus, he said, "I suggest that there ought to be a moratorium on new construction permits" while safety and control problems are worked out. He warned "there's a danger between now and 1985" when nuclear power will be needed to supply energy demands before other sources can be developed.

Anderson, obviously enjoying the attention of the large crowd; told the students he needs their "muscle power" during the fall campaign. An he asked them "to put the arm on your wealthy adult peers" to donate money to his efforts.

It was the second time in four days Anderson has appeared before a student crowd. On Saturday night, he gave one of the most effective speeches of his campaign before a group of about 1,500 students at the University of Wisconsin in Madison.

The campuses provide both an opportunity and a dilemma for the Illinois congressman. They provide many of the foot soldiers when he was running in the Republican primaries before he began his independent candidacy April 24. He will need the same foot soldiers this fall.

But he has to resist the temptation to concentrate too much on them as he attempts to broaden his political base, and raise enough money to wage a serious campaign.

This is particularly important during these first days of September. His campaign is in serious financial trouble.

According to a report filed with the Federal Election Commission on the campaign was $476,617 in debt on Aug. 1, and had only $132,246 in the bank. By contrast, Ronald Reagan and Jimmy Carter, nominees of the two major parties, each received $29.4 million in public money to conduct their campaigns.