In a series of fights pitting the Michigan automobile industry against Connecticut insurance companies and West Virginia coal producers against California environmentalists, the House Democratic leadership yesterday began filling vacancies on the choicest committees.

The Democratic Steering and Policy Committee proposed three new members for the Ways and Means Committee, which writes tax legislation, and four for the Appropriations Committee, which decides how much money federal agencies will receive.

These assignments, along with six openings on the Energy and Commerce Committee, which has regulatory jurisdiction over nearly every business activity, are critical to the outcome of legislative battles over such measures as the Clean Air Act and prospective tax increases.

They also give the newly assigned members access to many more campaign contributors.

Winning nomination to Ways and Means were Barbara B. Kennelly (Conn.), who is the daughter of the late Democratic Party leader John Bailey and whose district includes insurance-dominated Hartford; Byron L. Dorgan (N.D.), a proponent of tax reform, and Ronnie G. Flippo (Ala.), the most conservative of the candidates.

All nominations require approval by the full Democratic caucus.

In an unexpected development, one of Dorgan's earliest and strongest supporters on the Steering and Policy Committee was Charles Wilson (Tex.), a key advocate of the independent oil industry's interests. Wilson noted, however, "There is a hell of a lot of oil exploration in North Dakota and in Alabama."

Among those selected for the Appropriations Committee was Steny H. Hoyer (Md.), who in less than two years has developed strong ties to the leadership. His selection was particularly unusual because Maryland, a comparatively small state, already has Democrat Clarence D. Long on the committee.

Others selected for that committee included Bob Carr (Mich.), William H. Boner (Tenn.) and Robert J. Mrazek (N.Y.).

In other action, the steering panel appointed eight new members to the Budget Committee. They are Vic Fazio (Calif.), William H. Gray III (Pa.), Butler Derrick (S.C.), George Miller (Calif.), Geraldine A. Ferraro (N.Y.), Howard Wolpe (Mich.), Martin Frost (Tex.) and Pat Williams (Mont.).

Delayed until later this week was the battle for seats on the Energy and Commerce Committee. It has steadily grown in importance in recent years, with jurisdiction over such questions as the Clean Air and Clean Water acts, toxic waste, restrictions on the Federal Trade Commission and hospital cost containment.

As these issues have come to the fore, the level of campaign contributions to the panel's members have shot up, rivaling those of the members of Ways and Means and Appropriations. Just after the Nov. 2 election, 31 House members told the leadership they were interested in being assigned to Energy and Commerce.

In some quarters, the contest for such assignment is being described as a battle between John D. Dingell (Mich.), who has strong ties to the automobile industry and has sought to weaken car pollution requirements, and Rep. Henry A. Waxman (Calif.), leading Energy and Commerce proponent of maintaining tough pollution standards.

Among many candidates for the committee are several members from coal regions, including Alan B. Mollohan (W.Va.) and Frederick C. Boucher (Va.). Included among candidates seen as having strong ties to environmentalists are Peter H. Kostmayer (Pa.), Mel Levine (Calif.) and Robert G. Torricelli (N.J.).

Waxman, however, contended that seeing the battle as a contest between pro-industry members and pro-environment members would distort his differences with Dingell because they are allies on several issues.