A little election in Michigan, four days after Pennsylvania's, will be another pivot point for Sen. Edward M. Kennedy in his bid to wrest the Democratic nomination from President Carter.

Like Pennsylvania, it is the kind of state that offers Kennedy the potential of a strong showing, if not a victory. The state's politics are practically controlled by the powerful United Auto Workers, and the union's leaders have endorsed Kennedy almost unanimously.

Frank Kelly, the state's attorney general and highest elected Democratic official in the state, also has endorsed Kennedy, as have nearly half of the members of the state House.

Economic issues also should play well for Kennedy in this state, Michigan's unemployment rate in March was 10.2 percent, the highest jobless rate in any major industrial state. Layoffs in the automobile industry are expected to hit 223,000 this week, the most since the 1975 recession.

But unlike Pennsylvania, the campaign here will be a largely invisible one -- a war of telephones, with few personal appearances by Kennedy or surrogates.

That is because Michigan Democrats, will for the first time in two presidential elections, be allotting their convention delegates at a series of party caucuses across the state the night of April 26. Only registered party members will be allowed to attend the caucuses, and the registration deadline for membership was last Feb. 26. Only 41,717 Democrats met the deadline.

With such a small number of voters -- and with each of them easily identifiable from the list of registered party members -- the candidates have the opportunity to contact every potential Democratic voter several times between now and April 26.

The Carter-versus-Kennedy battle here is shaping up as an intense intraparty fight between the political machines of Detroit Mayor Coleman Young, who is backing Carter, and longtime Kennedy ally Douglas Fraser, president of the UAW.

The Young faction set the tone early. The Democratic Party chairmen of two vital congressional districts -- both allies of Young -- have refused to turn over to the Kennedy camp the lists of Democrats registered to vote in the party caucuses.

The Carter campaign has had the lists for about a week, and has been using them in a massive telephone campaign.

Malcolm Dade, a longtime Young political aide now Carter's deputy national campaign director, explained the policy of withholding the voter lists from the Kennedy camp: "To the victors belong the spoils, and we are in control."

In the last two presidential elections, Michigan Democrats selected their convention delegates in a presidential primary. But in the Democratic Party's new bylaws the state's primary was found in violation of a rule that forbids open primaries.

When the state legislature was unable to agree on a new nominating system in time to meet the national party's deadline, the Democratic primary was allowed to die. The party caucuses will be used to select and allot 141 national convention delegates.

But Michigan's Republicans will still be selecting their convention delegates in a primary, to be held this year on May 20. That primary is open, so Democrats -- even those who participate in the April 26 Democratic caucuses -- could vote in the GOP primary next month.

The potential for large numbers of Democrats voting in the Republican primary could be a boost to the flagging campaign of Rep. John B. Anderson (R-Ill.), who has been relying on large numbers of Democratic and independent crossover votes.

But Michigan's open primary also could be a boost to Republican front-runner Ronald Reagan, who has been gathering the support of blue-collar Democrats in his earlier primary victories. Michigan is about 41 percent blue collars, and is the state that George Wallace won by 51 percent in the Democratic primary in 1972, the day after he was shot in Maryland.

A Circuit Court judge in Lansing issued a temporary injunction last week blocking the May 20 primary because the state has refused to appropriate money to reimburse local governments for the election costs.

The same judge issued a similar restraining order before the 1976 presidential primary. That injunction was reversed by the appellate courts, however, and the primary was conducted on schedule.