The Charleston Post and Courier reported that employees of the plant were told Friday about the closing, which is blamed on weak demand for Class 8 trucks.
"We hope to get back into operation at the end of the three-week period and back to previous production levels, as soon as the industry gets back to some normalcy," Perry Lubbers, manager of the Western Star plant, told the paper.
Western Star's 285,000-square-foot assembly plant was designed to turn out 20,000 vehicles a year but has never approached that level of production. Western Star temporarily closed its Canadian assembly plant earlier this year, just as it was moving ahead with production in the Charleston plant.
Weakening truck sales are also being blamed for the $454 million consolidation of Western Star and a division of DaimelerChrysler AG announced last week.