The San Luis Potosí plant assembles two vehicles for GM: the Chevy Equinox and GMC Terrain. Notably, as part of GM’s recent announcement to invest $4 billion into U.S. manufacturing, the automaker confirmed it will build the next-generation Chevy Equinox at the Fairfax Assembly plant in Kansas.

This would not be the first time the San Luis Potosí plant has unionized. It was previously represented by a Confederation of Mexican Workers (CFM) affiliate, but voted out of it in 2023 since it was viewed as too friendly with GM. Afterward, GM made a labor council at the facility, but the members of the council were appointed by GM and were reportedly loyalists from the old union. The labor council disbanded when the SINITTIA campaign to represent the plant went public.

Since 2022, SINTTIA has represented the GM Silao plant and won significant annual raises for workers, including a raise as high as 10.25 percent for some workers earlier this year. GM has matched the Silao raises at the San Luis Potosí plant, which is about 90 miles away, likely in an effort to discourage the second plant from joining SINTTIA. The most recent raise at Silao raised two-thirds of the plant’s workers above Mexico’s poverty line.

At the rate raises have been coming in recent years, SINTTIA believes Mexican GM workers could reach parity with U.S. workers within a decade. If the San Luis Potosí plant votes to join the union, it will have even more leverage to make that goal possible.