Union members are leaving the assembly lines to set up picket lines at 33 plants across the USA as well as 22 parts warehouses.
"We are standing up for fair wages, we are standing up for affordable, quality health care", Dittes said on Sunday.
Union contracts with Ford and Fiat Chrysler were also due to expire, but have been extended indefinitely.
GM's statement regarding the stalled labor negotiations indicated that the company had promised the UAW to offer "solutions" for workers impacted by these plant closures, but did not indicate what those solutions were.
For now, the strike isn't anticipated to impact the immediate availability of most GM vehicles.
But several Democratic presidential candidates said they backed the UAW, including Senators Bernie Sanders and Kamala Harris, former Vice President Joe Biden and Representative Tim Ryan. The union's top negotiator said in a letter to the company that the strike could have been averted had the company made its latest offer sooner.
UAW leaders from across the country voted overwhelmingly here Sunday to authorize the action, instructing almost 46,000 blue-collar workers at 31 GM plants to either walk off the job or stay home. "We are fighting for the future of the middle class", he said.
Last week, UAW regional director Vance Pearson, who oversees 17 states, was arrested on six charges, including embezzlement of union money and money laundering, according to The Detroit Free Press. Picket line schedules already have been posted near the entrance to one local UAW office in Detroit.
But union spokesman Brian Rothenberg said they have come to terms on only 2% of the new four-year contract.
It would also make it impossible to do build specially ordered cars and trucks. GM pays $63 per hour in wages and benefits compared with $50 at the foreign-owned factories. The length "depends on how far apart they really are and where the lines in the sand are drawn", she said.
Had it been offered earlier, a strike may have been averted, "but they (GM) just put them up against a wall", Morgan said.
GM announced plans in November of 2018 to shut the Detroit and Lordstown assembly plants, along with transmission plants in Baltimore and Warren, Michigan.
On Sunday, about 200 plant-level leaders voted unanimously to strike against GM if no deal could be reached by Sunday night.
The UAW says significant differences remain between both sides over wages, health care benefits, temporary employees, job security and profit sharing.
Earlier, unions appealed to more than 46 thousand workers at 31 facilities calling to leave their workplace or to refuse to perform their work duties until further notice.
Mr Jones didn't attend the press conference but was quoted in the union's statement that called the strike.
- The union also wants new products for the four factories slated to close.
Sanders noted GM received a US -taxpayer funded $50 billion bailout a decade ago.
Automotive Editor Gary Gastelu weighs in on GM profits. Union members working Sunday were to report as scheduled.