Ford Motor Company announced late last night that it will add a third week to its previously-announced two-week holiday shutdown for 10 of its 12 North American assembly plants. While most of the automaker’s plants will reopen January 12, Ford’s F-150, Escape and Mercury Mariner assembly plants will reopen a week earlier in response to demand.

In response to weak new car demand that is plaguing every automaker, Ford intends to trim production for the first quarter of 2009 to just 430,000 cars in North America - down 37.9 percent over 2008’s figures.

The announced cuts won’t eliminate the nearly 38 percent Ford is seeking to reduce, so expect further plant idling announcements to come.

Ford says the River Rouge plant in Dearborn, Michigan, which produces the F-150, and the Claycomo, Missouri, plant that produces the Escape and Mariner will open on January 5.

Production will then fire back up the week of January 12th, with the exception of Ford’s Hermosillo, Mexico, and Oakville, Ontario, plants. The Hermosillo plant produces the Ford Fusion, Mercury Milan and Lincoln MKZ, while the Oakville plant is responsible for the Ford Flex, Edge and Lincoln MKX. Both plants should be back online by February. The Hermosillo plant is down to retool for the 2010 models - don’t miss Leftlane’s review of the ‘10 Fusion.

Ford also plans to extend the shutdown at some of its engine, transmission and stamping plants.

The automaker blames the slump in new car demand for the additional week of closure. Yesterday, Chrysler announced that it will close all of its plants for four weeks beginning Friday and similar, albeit not as all-encompassing, announcements have been made by nearly every automaker all over the world.