Former secretary of state Alexander M. Haig Jr. yesterday dismissed all speculation that he may seek the presidency, and said "it's essential" for President Reagan to run for a second term.

Haig, in a CBS television interview, ruled himself out of the 1984 presidential race for personal and political reasons, including the dispute that surrounded his resignation as secretary on June 25.

His 18 months at the Department of State were "a period of great frustration for me," Haig said, and "some of the manifestations" of that "were evident to all."

"Despite some flirtations" on his behalf at one stage about a presidential candidacy, Haig said, "The conclusions I drew several years ago have been reinforced by recent experiences, and no, I have no presidential aspirations, despite the suspicions of whoever may harbor such suspicions."

When asked if he believes Reagan should run again, Haig replied, "I think it's essential."

Haig's comments came in the third installment of a three-part interview with correspondent Diane Sawyer on the CBS "Morning News," taped earlier. At the University of Michigan yesterday, Haig joined former president Gerald R. Ford, and former secretaries of state Dean Rusk and William P. Rogers, in a conference on the presidency.

At the Ann Arbor meeting, all agreed that the Reagan administration is correct in seeking to end the controversy with America's allies over sanctions imposed on them over the Soviet natural gas pipeline. A major flash point in Haig's forced resignation was his opposition to Reagan's decision to levy sanctions on Western nations selling equipment for the pipeline.

In Haig's televised interview, the former secretary added only a few new fragments to his turbulent tenure as presidental "vicar" for foreign policy, which he avoids discussing in any detail.

Haig said that in the "three weeks prior to inauguration" in 1981, he worked out lines of authority with incoming Defense Secretary Caspar W. Weinberger; William J. Casey, director-designate of the CIA, and Richard V. Allen, Reagan's first national security adviser. But then, Haig said, "faceless staff people" at the White House charged him with trying "to seize control of the levers of government."

When asked why, with all his experience in government, he became such "a lightning rod" in the administration, Haig said there were "a host of reasons." Among them, he said: "I myself may have been guilty of some shortsightedness or lack of appreciation for the milieu in which I was working, or perhaps less than patient in my willingness to deal with . . . what I perceived to be shortcomings in them."

The Reagan administration has developed more consistency and clarity since he left government criticizing its deficiencies, Haig said, although "not to the degree that I had hoped." George P. Shultz, his successor, Haig said, had "made progress and I think my departure was a contributor to that progress."