DETROIT — A Canadian auto workers union called Unifor reached a tentative agreement late Monday night with Fiat Chrysler Automobiles, assuring uninterrupted production of Chrysler’s big sedans.

The deal includes a commitment to invest in the automaker’s assembly plant in Brampton, Ont., and provides its workers with their first raises in 10 years.

The deal was reached after several days of intense bargaining and, if ratified by workers, includes a $325 million investment in Brampton for a new paint shop and $6.4 million to upgrade the automaker’s casting plant in Ebitocoke, Ont., in Canadian dollars. It also includes $12,000 in bonuses and lump sum payments to workers over the life of the…