Nancy Clark Reynolds, a close friend of President and Mrs. Reagan, yesterday resigned as vice president for national affairs of the Bendix Corp. She will become a partner in Wexler and Associates Inc., a Washington-based public-affairs firm headed by Anne Wexler, a former aide to president Jimmy Carter, effective Dec. 31.

Reynolds takes with her an unrivaled access to the White House and the Reagans, whom she has known since she worked for Ronald Reagan when he was governor of California.

Bendix chairman William Agee, who grew up with Reynolds in Idaho, accepted the resignation. Sources close to Reynolds say she has not been comfortable at Bendix for several years and that she believed Agee and his wife, Mary Cunningham, no longer wanted her at the company.

Reynolds and Wexler said the move has been in the works for some time. "We have been talking about this since last February," said Reynolds. "I have always wanted to do something entrepreneurial and the time was right."

Reynolds, who has been at Bendix for five years, denied that she resigned because of Cunningham, now an executive of Joseph E. Seagram and Sons Inc. "That would not be fair to Mary," she said.

"Listen, they know how much I love my job," she said. "I'm just writing Bill Agee a letter thanking him for the opportunity to run the corporate office. I deeply appreciate all he has done for me."

Two years ago, Reynolds reportedly warned Cunningham -- then an executive of Bendix and not yet married to Agee -- that it was imprudent to be seen in social situations with her boss. This advice, sources say, strained relations between the two women, as well as between Agee and Reynolds.

"Good Lord. I have no comment on that," said Cunningham when reached in New York.

Agee could not be reached for comment yesterday.

Harold S. Barron, vice president, secretary and general counsel of Bendix, and the person to whom Reynolds submitted her letter of resignation, said yesterday, "I've been her supervisor for over two years. This is a professionally managed company and if there are some personal relations that are not 100 percent, they don't stand in the way. I haven't observed anything to give credence to that speculation ." See REYNOLDS, D4, Col. 5 REYNOLDS, From D1

Barron said Reynolds was leaving because "this is something that she wanted to do. It's her style to do something like this. We'll miss her at the company." He later added, "Slavery was abolished with the 14th Amendment. We can't keep anybody who doesn't want to stay."

Bendix issued a statement reading in full: "The Bendix Corporation today announced the resignation of Nancy Clark Reynolds, vice president of national affairs, effective December 31. Ms. Reynolds will become a full partner at Wexler, Reynolds, Harrison and Schule Inc."

Wexler said the name of her firm will be changed Jan. 1 to reflect the addition of her new partner. Gail Harrison and Robert M. Schule already work with Wexler. A consulting and lobbying firm, Wexler and Associates represents such clients as the National Football League, the Motion Picture Association of America and Aetna Life Insurance.

Wexler was also retained by Bendix to assist in the company's recent attempt to acquire Martin Marietta. Wexler worked with Reynolds on that project.

Reynolds said she chose from among five job offers, deciding Wexler's firm best suited her interests. "This is going to be a fun job and I have developed an enormous amount of respect and admiration for Anne since we have been working together," said Reynolds.

Reynolds, 55, took leave from her job at Bendix first to work in the 1980 Reagan presidential campaign and then to serve as head of Nancy Reagan's transition team. The two women became close in Sacramento, and Reynolds has been one of Nancy Reagan's staunchest defenders over the past two years.

Before joining Bendix, Reynolds was associate director for national affairs at the Boise Cascade Corp., where Agee also worked. Earlier, before joining Reagan's gubernatorial staff, she was the first woman coanchor on KPIX-TV news in San Francisco.