The protracted battle between manufacturers of mobile homes and a major consumer group representing the people who live in them is heating up again.

Industry-backed legislation seeks to overhaul the nation's 25-year-old law regulating mobile home construction and safety. But blocking the way of what it calls a weakening of national standards is the group whose members own the biggest percentage of mobile homes, AARP.

AARP (which has changed its legal name from the American Association of Retired Persons), government and the industry all agree that the creaky law needs a major tuneup. But AARP and the industry are miles apart over the basic issue: whether manufactured houses today are significantly better than the shoddy trailers that spawned minimum national safety and durability standards. Consequently, in this increasingly contentious debate, the two sides are miles apart over how to repair the law.

The industry's main goal is to get its regulator, the Department of Housing and Urban Development, going on updating manufacturing codes, to reflect changes in construction technology that are reshaping how manufactured homes look.

As the legislation picks up steam this week, AARP is trying mightily to redirect the proposal. AARP acknowledges that HUD is woefully behind in keeping up with technology. But the group believes the real problem is that current regulations don't ensure quality and aren't enforced. AARP wants to add mandatory five-year warranties and federal installation standards and to remove language in the Senate and House bills that would let a new advisory committee initiate regulation and enforcement. AARP also believes the committee is stacked in the industry's favor.

Just as vigorously, the Arlington-based Manufactured Housing Institute and other industry groups object to mandated warranties and federal installation requirements and insist the focus should be on keeping houses affordable by speeding HUD action.

HUD testified in support of the House bill, but Thursday night Assistant Housing Secretary William C. Apgar said he was still preparing his testimony on the Senate bill and had concerns about portions of it.

The industry is pressing for votes before Congress recesses for Thanksgiving. A hearing is set for Tuesday on S. 1452 before a Senate banking subcommittee. A House subcommittee held a hearing on two bills Sept. 15 and could vote at any time.

Although the battle to change the law has gone on almost since the day it was enacted, the industry hopes this year could be the charm because House sponsors have tucked the language into an omnibus housing bill that has broad bipartisan support.

About 8 percent of Americans--more than 19 million people--live in manufactured homes. And they account for a quarter of new single-family dwellings. The heaviest concentration is in the South. Because mobile home owners aren't organized nationally, AARP says it is acting on behalf of its many members living in these homes. About 44 percent of mobile homes are owned by people 50 and older.

"Industry has testified that problems are really a thing of the past," said Roy E. Green of AARP. But, in a poll released the day the Senate bill was introduced in July and conducted by the same firm that does the industry's polls, AARP found "startling results," said Green. "Seventy-seven percent of new homeowners, more than three-fourths of the people, said they had one or more problems" with their manufactured houses. And, although 95 percent of the 933 owners had warranties, only a third of the problems were repaired under warranty, said Green.

"What do you think the reaction would be if you bought a $35,000 to $40,000 car and three-quarters of the people who bought them reported having a problem? People would be outraged," said George Corey, a Boston technology consultant who helped write the 1974 law and is aghast at the industry's proposals.

The Industry, meanwhile, contends that its polls show 80 percent of new owners are satisfied and that its legislation would strengthen, not weaken the federal program.

"Certainly our problems are not as severe as AARP and their survey paint them to be," wrote Chris Stinebert, president of the Manufactured Housing Institute (MHI), in a September trade journal. "And even more certainly the problems of a small sample of homeowners do not reflect the state of the entire industry."

At the Sept. 15 hearing, Edward Hussey, chairman of an industry group and vice president of Liberty Homes Inc., said the bills would actually "give consumers, for the first time, a real voice . . . through direct participation in consensus proceedings."

Hussey was referring to the bills' "consensus committee." The committee would recommend revisions in standards and how they are enforced. The revisions would become law unless the secretary of HUD stopped them.

"Trust me, the secretary will react to the things they feel are going to hurt consumers," said Kami Watson of MHI.

But AARP says the committee is flawed in composition and scope. The panel would have five consumers, five manufacturers, five representatives of others in the industry such as retailers or lenders, five public officials and five representing the "general interest" such as architects or developers.

Though the bills say the 15 people outside the industry cannot have a significant financial interest in manufactured housing or a significant relationship to someone in the industry, Green said the restrictions "would be quite easy to circumvent. . . . Because mobile home owners are not organized across the country, there would be quite an opportunity to front-load the committee."

He added that the bills exempt the committee from conflict-of-interest laws. "It's truly like having a fox in the chicken coop," said Green. AARP wants three groups with seven members apiece representing consumers; manufacturers and dealers; and public officials and the general interest.

Watson said the 15 outside members would be "absolutely and completely unrelated" to the industry. And she noted that the Senate bill requires not just a majority vote, but a two-thirds vote. She added that a national commission tried using three groups of seven and failed to reach agreement.