The financially faltering FANS (Fight to Advance the Nation's Sports), launched a year ago by Ralph Nader as a sports consumer's rights group, is shifting its headquarters here to San Francisco in search of more support and money.

Peter Gruenstein, executive director of FANS, said yesterday the 1,400-member organization is in need of an overhaul and would better "survive and grwo" in San Francisco.

"The people there are most enthusiastic about getting a local chapter going," Gruenstein said. "The concept now is to build FANS from the bottom up."

FANS was founded last September to represent sports fans before professional and amateur sports organizations, Congress, the media, federal agencies and the courts. It was to be, in essence, a lobbyist for the average fan.

Nader and Gruenstein said FANS members would participate in policy-making and exert influence through economic boycotts and court challenges.

Gruenstein said recently the future of the organization would be in jeopardy unless finances improved.

Ironically, one of FANS' biggest problems in getting off the ground, Gruenstein said, was its identification with Nader, who provided $20,000 in loans to start up the group.

Nader has acted only in an advisory capacity since he introduced Gruenstein and the FANS concept at a press conference here last September.

"All of Ralph's other group are funded, and people just assumed we were," Gruenstein said. "They didn't realize we're a membership organization, dependent on membership fees. We were very much on our own."

Income from membership fees, $9 a year, has been insufficient to pay salaries for a staff of five and office expenses - let alone repay Nader's loans. Operating costs recently have been met by speaking honorariums and free-lance articles by Gruenstein and staff members.

Gruenstein, who is temporarily on leave from FANS to work on a political campaign, also blamed the news media for some of the problems.

"We really got burned by the press through poor reporting that distorted what we were doing," he said. He cited exaggerated accounts that FANS would demand veto rights in the firing or trading of players by clubs, adding he has spent the past year debunking the reports.

The organization also was the subject of humorous articles and broadcasts teasing that Nader was really plotting to replace hot dogs and beer at the ballpark with wheat germ and carrot juice.

Gruenstein said yesterday the positive aspects of FANS have not been highlighted. He cited the group's call for an appreciation night for Bob Lurie, president of the San Francisco Giants, for fighting to keep the club there despite heavy financial losses.

San Francisco would be an ideal location for the group's first chapter and headquarters, he said, because of the enthusiasm shown there recently. Boston, which he called "the most fanatical sports town in the country," would be perfect, he said. Nevertheless, Gruenstein said he would retain his own base in Washington, not San Francisco.

"Washington is one of the last places you should try to develop a local chapter," he said. "It's not a good sports town. It's a good football town.

"The only logic for our beginning in Washington was that Congress is there and the government, so it's good for lobbying purposes. But there's little lobbying done by FANS."