Ford Motor Co. will shed the last line of business in 9-year-old Automotive Component Holdings LLC by December when ACH closes its Plymouth, Mich., climate control plant in and lays off its last 257 employees.

The subsidiary created by Ford on Oct. 1, 2005, to take over plant operations from former in-house parts supplier Visteon Corp., has been gradually shifting its heating, ventilation and cooling production work to Detroit Thermal Systems LLC. Detroit Thermal Systems is a minority-owned joint venture between Redford Township, Mich-based V. Johnson Enterprises LLC and French supplier Valeo SA. It wascreated in late 2012, and maintains a 365,000-square-foot plant in Romulus, Mich.

The Plymouth plant had in-house injection molding and also housed some former ACH radiator business that Ford was able to place with other suppliers some time ago, leaving only the HVAC business that was moving to Detroit Thermal Systems, said Janet O’Brien, manager of human resources for ACH. The last of that business should leave the Plymouth facility in mid-December, causing ACH to lay off the remaining employees and close the plant, she said.

The company is letting go of 166 hourly workers and 91 salaried employees, according to a notice obtained earlier this month by the state Workforce Development Agency under the federal Worker Adjustment and Retraining Notification Act. O’Brien, who filed the notice, said Detroit Thermal Systems has so far absorbed more than 400 former ACH employees after buying the HVAC business in 2012 — but it was not immediately clear if the Romulus plant would employ the remainder working in Plymouth.

Earlier this year, ACH reported $90 million in injection molding sales for 2013 in Plymouth, using 27 presses for Plastics News’ annual injection molders rankings.

Those sales were down sharply from 2012, when it had $200 million, reflecting changes at the site.

Visteon spun off from Ford in 2000. Ford created ACH in 2005 to take over unprofitable business lines and operations from Visteon. The Dearborn, Mich.-based carmaker said from the start its intent was to sell those businesses or shut them down if needed.

Visteon eventually still was forced into bankruptcy to restructure in 2009 and emerged in October 2010.

Vinnie Johnson, chairman and CEO of The Piston Group and partner with Valeo at the Romulus plant with V. Johnson Enterprises, could not be immediately reached for comment. An executive assistant contacted by Crain’s Detroit Business, which is a sister publication of Plastics News,confirmed that Detroit Thermal Systems has been handling that ACH legacy business in Romulus but was unfamiliar with the WARN notice.

The federal act generally requires companies with more than 100 employees to notify state and local government officials 60 days before closing a plant or building or laying off that affect more than 50 employees. But a notice can often mean a business has lost a contract to another company which will assume those contract’s employees, or transfer jobs elsewhere.

Dawn Booker, communications manager for Ford Motor Land Development Corp. in Dearborn, and O’Brien confirmed that Ford Land will take possession of the Plymouth plant as part of the part of the automaker’s real estate subsidiary land portfolio, after the plant closing. Plans for the Plymouth facility after ACH are still in development, she said.

“There’s not a fully formed plan yet. At this point, the focus is on transitioning the last of the business out of that plant and getting prepared for closing,” she said.

Ford created two new minority-owned joint ventures in 2012 to assume some ACH business — Detroit Thermal and Detroit Manufacturing Systems LLC, co-owned by Andra Rush and French supplier Faurecia SA.

In the Detroit Manufacturing deal, Faurecia assumed partial operation of the massive ACH interiors plant in Saline, Mich., and transferred a bulk of the $1 billion interiors business to the Detroit Manufacturing plant in Detroit.

Urbana, Ill.-based Flex-N-Gate Corp. acquired a Sandusky, Ohio, ACH lighting and air storage plant in 2012, leaving Plymouth as the final piece in the ACH puzzle.