General Motors Corp. moves up the closure of a truck plant in Janesville, WI, to Dec. 23, as the auto maker continues to wrestle with plunging demand for its large SUVs.

GM announced in June plans to close the assembly plant by the end of 2010, saying it could shutter the facility earlier if demand weakened further. The auto maker also has moved ahead closure of its, Moraine, OH, assembly plant due to weak demand from the end of 2010 to Dec. 23.

Janesville builds the Chevrolet Tahoe and GMC Yukon, while Moraine makes the Chevy TrailBlazer, GMC Envoy and Saab 9-7X midsize SUVs.

GM also plans to close a large pickup facility in Oshawa, ON, Canada, and will cease medium-duty truck production in Toluca, Mexico, as part of its strategy to align production with a shift in consumer demand to more fuel-efficient vehicles.

Light-duty truck sales through September are off 20.6% compared with the same period last year, according to Ward’s data, while deliveries of SUVs are down 36.1%.

jamend@wardsauto.com