After a successful late-night bargaining session, the Canadian Auto Workers Union and management at Johnson Controls have reached a tentative agreement on a new three-year labour deal.

The deal, which will be subject to a ratification vote set for Sunday at 1 p.m. ET, was struck early Saturday morning between management and workers of the plant located in Lakeshore, Ont., east of Windsor. Both sides had been in talks over a new contract since Monday. CAW representatives told CBC News they were confident the deal would be ratified.

If ratified, the deal means Johnson's 120 employees can remain on the job and thereby avoid interrupting production at Chrysler's Windsor assembly plant.

Johnson Controls builds overhead components, or headliners, for the Dodge Grand Caravan and Chrysler Town and Country minivans. Headliners involve wiring in the roof of vehicles and are installed during the earliest stages of assembly.

Without them, the Chrysler assembly plant would have to shut down in about three hours, forcing more than 4,500 plant workers off the job, said CAW Local 444 vice-president Dino Chiodo.

Even car dealers were worried about what a strike at Johnson Controls would do to business.

The two sides bargained until 9 p.m. Thursday night and were back at the table by 7 a.m. on Friday, Chiodo told CBC News. Job security was a key issue in the negotiations.

Johnson Controls' 2009 fourth-quarter sales dropped 15 per cent, from $9.3 billion US in 2008 to $7.9 billion in 2009, forcing the company to find new ways to cut costs.