Last week, the “Right to Repair” bill unanimously passed the Massachusetts House of Representatives, a landmark victory for the state's independent mechanics and chain shops. After a three-and-a-half year fight, one that saw automakers and dealers alleging the proposed new law would devastate their service businesses, those groups gave up. It’s amazing what a little public opinion can do.

In a survey of its Massachusetts members this year, AAA said that 88 percent were in favor of the bill. The Right to Repair Coalition, a lobby of 2,000 repair shops, gathered more than 100,000 signatures since last fall, guaranteeing a spot on the November ballot. These numbers, combined with the bill’s Senate approval in May, didn’t look good for the Alliance of Automobile Manufacturers or the Massachusetts State Automobile Dealers Association, which had opposed the bill on the grounds of protecting copyright and intellectual property (you can read our synopsis here).

Here’s the short story: Within 90 days of Gov. Deval Patrick’s signature, expected within the next week, all automakers will have to provide independent shops in Massachusetts full access to repair information, plus the ability to purchase factory-authorized computer scanning tools. Whatever the dealers get to buy, so do the small guys.

“I think the vehicle manufacturers kind of said, you know what, it’s better to have a compromise rather than go to a vote and lose completely,” said John Paul, AAA’s public affairs manager for New England.

No one really knows what the average car owner will save in the process, but it’s proven fact that the more free and open the market, the better the deals. Not having to pay a premium to switch off a “check engine” light or to reset an oil level sensor -- let alone being stuck to a single area dealership as the only point of service -- should be enough to persuade the other 49 states to get on board.

“It just makes sense to people. Why shouldn’t you get that?” said Art Kinsman, a registered lobbyist leading the Right to Repair Coalition. “It’s a reasonable expectation of the purchase price of the vehicle.”

By 2018, automakers selling cars in Massachusetts will be required to use a simplified interface of their choosing that can hook up to a laptop and download all necessary repair information. Kinsman said the law should encourage automakers to move more of their repair data to a cloud-based system, instead of requiring pricey hardware upgrades every few years as they do now. Dealers could benefit by being able to diagnose and fix trade-ins from other automakers, plus they’ll no longer be required to purchase factory-authorized tools, as per their current franchise agreements, Paul said.

General Motors had been “leading the charge” against a compromise bill, Kinsman said, referring to the amount of public testimony from GM and Chrysler representatives.

But there’s still a small conflict. It’s too late to remove the repair question from the November ballot, and that question -- which references an earlier version of the bill requiring automakers to comply with a single, standard interface by 2015 -- could easily pass. Kinsman said that if it does, lawmakers will be forced to go back to the current bill, which was rewritten in concession to automaker demands.

Similar bills had been introduced in other states, such as New Jersey, but none had become law. A separate, national “Right to Repair” bill is now stalled in the U.S. House of Representatives with 50 co-signers. But Californians have fought automakers for decades and won nearly every time. And when one state forces its hand on a big industry, others typically follow suit. So, we asked it before and we’ll ask it again: What do you think of this law, and do you could it could make your car maintenance significantly cheaper?