Diamond-Star Motors
Corporate brand
UnclaimedA Chrysler–Mitsubishi automobile-manufacturing joint venture whose Normal, Illinois, facility later became Mitsubishi's principal North American assembly plant.
Last updated August 22, 2026
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Overview
Diamond-Star Motors was an automobile-manufacturing joint venture formed by Chrysler Corporation and Mitsubishi Motors in the United States. Its name combined the defining symbols of the two parent companies: Mitsubishi's three-diamond emblem and Chrysler's pentastar. The venture was created during a period when Chrysler depended heavily on Mitsubishi-built compact vehicles to broaden its North American range, while Mitsubishi sought a stronger direct manufacturing and distribution presence in the United States. The partners incorporated Diamond-Star Motors in October 1985 after Chrysler and Mitsubishi had developed a substantial commercial relationship. Chrysler had held a minority stake in Mitsubishi and distributed Mitsubishi vehicles in the United States under Chrysler, Dodge, and Plymouth branding. The arrangement gave Chrysler access to fuel-efficient small cars, but it also created strategic tension as Mitsubishi expanded its own branded dealership network and sought to sell more vehicles directly. A domestic manufacturing operation offered both companies a way to reduce dependence on imported vehicles and navigate the import restrictions affecting Japanese automakers at the time. Illinois secured the project through a large public incentive package and an intensive state and local lobbying effort. Construction of a roughly 1.9-million-square-foot facility in Normal began in April 1986. The plant was completed in March 1988 with a stated annual capacity of approximately 240,000 vehicles. Its first major products were the Mitsubishi Eclipse, Plymouth Laser, and Eagle Talon, closely related 2+2 sports cars built on a jointly developed platform. These vehicles later became strongly associated with the abbreviation DSM among automotive enthusiasts, especially when referring collectively to the first- and second-generation Eclipse, Talon, and Laser. Diamond-Star Motors subsequently produced a broad range of Mitsubishi and Chrysler-branded vehicles. The product mix included Mitsubishi Mirage derivatives sold as Dodge, Plymouth, or Eagle compact cars; the Mitsubishi Galant; and Chrysler and Dodge coupes such as the Sebring Coupe and Avenger Coupe. The facility also built vehicles based on Mitsubishi platforms, including the Endeavor, Galant, and Eclipse. Chrysler and Mitsubishi initially operated the venture on an equal basis, but Mitsubishi bought Chrysler's interest in 1991. Chrysler-branded production continued under contractual arrangements, and the companies continued selected manufacturing cooperation after the ownership change. The corporate identity changed after Mitsubishi assumed control. The operation was renamed Mitsubishi Motor Manufacturing of America, Inc. in July 1995. From 2002 through 2016 it operated under the Mitsubishi Motors North America name with a manufacturing-division designation. The Normal site was expanded in 2003 and, from mid-2012, assembled the Mitsubishi ASX, marketed in the United States as the Mitsubishi Outlander Sport. Mitsubishi announced in July 2015 that it would end vehicle production at Normal because the factory had operated substantially below its designed capacity for several years. Production ended on November 30, 2015, while a reduced workforce remained to manufacture replacement parts until the plant's final closure in May 2016. The facility and its manufacturing equipment were subsequently liquidated and acquired by Rivian in January 2017 for use as that company's principal North American manufacturing site. Diamond-Star Motors therefore survives primarily as a historical corporate and manufacturing identity, as well as an enthusiast term for the shared Mitsubishi-Chrysler sports-car platform and its related vehicles.
History
Diamond-Star Motors developed from the expanding commercial relationship between Chrysler Corporation and Mitsubishi Motors. Chrysler had taken a 15 percent interest in Mitsubishi in 1970 and subsequently distributed Mitsubishi-built vehicles in the United States under Chrysler, Dodge, and Plymouth names. These captive imports, including the Dodge Colt, helped Chrysler compete in the compact-car market during the 1970s, when demand for smaller and more fuel-efficient vehicles increased. By 1982, Chrysler was importing approximately 110,000 Mitsubishi vehicles annually. The arrangement became more complicated as Mitsubishi wanted to sell vehicles directly through its own branded American dealerships. The United States was operating a voluntary quota system that restricted Japanese vehicle imports, and Mitsubishi's direct sales affected how vehicles were counted against Chrysler's allocation. Chrysler also held a right of first refusal over Mitsubishi automobiles sold in the United States until 1990. A joint American manufacturing project could address these commercial tensions while giving Mitsubishi a domestic production base. The companies incorporated Diamond-Star Motors in October 1985. Illinois won the factory project after offering an incentive package reported at $274 million and mounting a substantial state and local campaign to attract the investment. Groundbreaking took place in April 1986 in Normal, Illinois. The approximately 1.9-million-square-foot facility was completed in March 1988 and was designed for annual production of about 240,000 vehicles. The plant's early workforce produced three closely related sports coupes: the Mitsubishi Eclipse, Plymouth Laser, and Eagle Talon. Their shared engineering and manufacturing origins later made “DSM” a common enthusiast abbreviation for the cars and, in some contexts, for the platform itself. The initial product program expanded beyond the sports-coupe trio. During the following decade the facility built Mitsubishi Mirage-related compact sedans and their Dodge, Plymouth, and Eagle derivatives, as well as the Mitsubishi Galant. It also assembled Chrysler Sebring and Dodge Avenger coupes. In 1989, plant employees formed United Auto Workers Local 2488 and concluded their first contract with the company. Diamond-Star Motors began as a 50–50 Chrysler–Mitsubishi venture. Mitsubishi purchased Chrysler's interest in 1991, after which Chrysler vehicles continued to be produced on a contractual basis. Chrysler's equity stake was sold to Mitsubishi in 1993. On July 1, 1995, the facility was renamed Mitsubishi Motor Manufacturing of America, Inc., formally ending the Diamond-Star Motors corporate name even though the Normal operation continued manufacturing Mitsubishi and Chrysler-related vehicles. From 2002 to 2016, the operation used the Mitsubishi Motors North America name together with a manufacturing-division designation. The Normal factory continued to assemble vehicles based on Mitsubishi platforms, including the Endeavor, Galant, and Eclipse. A 2003 expansion increased the building to approximately 2.4 million square feet. In mid-2012, production began on the Mitsubishi ASX, sold in the United States as the Outlander Sport. The highly mechanized facility employed approximately 1,900 people and used about 1,000 robots, according to the reference account. Mitsubishi announced in July 2015 that production would cease because the plant had been operating well below capacity for several years. The facility reportedly built just over 61,000 vehicles in 2014 against annual capacity of 240,000. Production ended on November 30, 2015. Approximately 900 of the roughly 1,200 remaining workers were laid off at that point, while the rest stayed to produce replacement parts until the final closure in May 2016. The plant was subsequently transferred through a liquidation process involving Maynards Industries. Rivian acquired the facility and its manufacturing contents in January 2017 for $16 million and made it the foundation of its North American manufacturing operations. In May 2024, Rivian announced a planned expansion intended to support production of its R2 midsize SUV. The proposal described more than 2.1 million additional square feet, including a new 1.1-million-square-foot building, and projected overall capacity of approximately 215,000 vehicles annually. Thus, although Diamond-Star Motors itself is defunct, its former factory remains an important automobile-manufacturing site.
- 2024
Rivian announces planned R2 expansion
[1]Rivian announced a proposed expansion of the former Diamond-Star Motors site to support R2 production.
- 2017
Rivian acquires the facility
[1]Rivian purchased the plant and manufacturing contents for $16 million.
- 2016
Final plant closure
[1]The remaining replacement-parts operation ended and the former Mitsubishi facility was transferred through liquidation arrangements.
- 2015
Vehicle production ends
[1]Mitsubishi ended vehicle assembly at Normal on November 30 after prolonged underutilization.
- 2012
Outlander Sport production begins
[1]The Normal operation began assembling the Mitsubishi ASX, marketed domestically as the Outlander Sport.
- 2003
Plant expansion
[1]Expansion increased the facility's reported area to approximately 2.4 million square feet.
- 1995
Corporate name changes
[1]Diamond-Star Motors was renamed Mitsubishi Motor Manufacturing of America on July 1.
- 1991
Mitsubishi assumes sole ownership
[1]Mitsubishi bought Chrysler's interest in the joint venture.
- 1989
First union contract
[1]Workers formed UAW Local 2488 and signed the plant's first labor contract.
- 1988
Normal plant completed
[1]The facility was completed with planned annual capacity of approximately 240,000 vehicles.
Products and positioning
A North American vehicle-production partnership combining Mitsubishi engineering and manufacturing with Chrysler distribution, branding, and market access.
Sports coupe · 1988
Mitsubishi Eclipse
The Eclipse was one of the three launch vehicles associated with the Normal plant and shared a jointly developed platform with the Eagle Talon and Plymouth Laser. The first and second generations became especially prominent in enthusiast culture under the DSM label. Production at the facility formed part of the early identity of the Chrysler–Mitsubishi manufacturing partnership.
Sports coupe · 1988
Eagle Talon
The Eagle Talon was Chrysler's Eagle-branded member of the shared sports-coupe program produced at Normal. It was closely related to the Mitsubishi Eclipse and Plymouth Laser, using the same basic vehicle architecture. Along with those models, it is commonly included in the enthusiast meaning of “DSM.”
Sports coupe · 1988
Plymouth Laser
The Plymouth Laser was the Plymouth-branded version of the three-car sports-coupe program that established Diamond-Star Motors production. It shared its fundamental platform and manufacturing lineage with the Mitsubishi Eclipse and Eagle Talon. The model represented the venture's effort to combine Mitsubishi product engineering with Chrysler group branding.
Compact car
Mitsubishi Mirage and related compact sedans
The Normal operation later produced Mitsubishi Mirage-related compact sedans and derivatives marketed under Dodge, Plymouth, and Eagle names, including Colt and Summit variants. These vehicles broadened the plant's output beyond sports coupes and reflected the original partnership's emphasis on small, fuel-efficient automobiles for the North American market.
Midsize sedan
Mitsubishi Galant
The Mitsubishi Galant was among the larger passenger-car lines assembled at the Normal facility. Its production demonstrated the plant's evolution from a specialized sports-coupe site into a broader Mitsubishi manufacturing operation capable of producing mainstream sedans for the North American market.
Sports coupe
Dodge Avenger Coupe and Chrysler Sebring Coupe
The Dodge Avenger Coupe and Chrysler Sebring Coupe were Chrysler-branded coupes manufactured at the Normal facility through the companies' cooperative production arrangements. Their presence continued Chrysler's use of the plant after Mitsubishi became the sole equity owner of the operation.
Sport utility vehicle
Mitsubishi Endeavor
The Endeavor was one of the Mitsubishi vehicles built at the former Diamond-Star Motors facility after the operation had become Mitsubishi-controlled. It represented the plant's move into sport utility vehicles and its use of Mitsubishi platform architectures beyond the original compact and coupe programs.
Compact crossover SUV · 2012
Mitsubishi Outlander Sport
The Mitsubishi ASX entered production at Normal in mid-2012 and was sold in the United States as the Outlander Sport. It was the final major Mitsubishi vehicle line identified with the site's late production period, before Mitsubishi ended assembly and shifted North American supply to imported vehicles.
Brand decisions
2024
Plan expansion for Rivian R2 productionStrategyBackground
Rivian continued developing the former Mitsubishi site as a major North American manufacturing base and identified the facility for production of its R2 midsize SUV.
Action taken
Rivian announced a planned expansion covering more than 2.1 million square feet, including a new 1.1-million-square-foot building for body shop, general assembly, and end-of-line operations.
Aftermath
The announced plan projected total site capacity of approximately 215,000 vehicles annually and was associated with a proposed Illinois incentive package.
Planned expansion investment. $1.5 billion (Announced May 2024)
2017
Sell the former plant and equipment to RivianM&ABackground
Following Mitsubishi's closure and liquidation process, the production-ready facility became available for a new automotive manufacturer.
Action taken
Rivian acquired the plant and its manufacturing contents in January 2017.
Aftermath
The site became Rivian's primary North American manufacturing facility, preserving its role as an automobile-production location despite the end of the Diamond-Star Motors and Mitsubishi identities.
Acquisition price. $16 million (January 2017)
2015
End vehicle assembly at NormalStrategyBackground
The plant had operated well below its designed annual capacity for several years. Mitsubishi reported production of just over 61,000 vehicles in 2014 against capacity of approximately 240,000.
Action taken
Mitsubishi announced in July 2015 that vehicle production would end, with assembly stopping on November 30 and a smaller replacement-parts operation continuing temporarily.
Aftermath
Most of the remaining workforce was released when assembly ended. The final parts operation ceased in May 2016, and the site entered a sale and liquidation process.
2012
Begin local production of the Outlander SportProduct launchBackground
Mitsubishi continued using the Normal facility for selected North American vehicle production.
Action taken
The plant began assembling the Mitsubishi ASX, marketed in the United States as the Outlander Sport.
Aftermath
The crossover became part of the facility's final production phase before Mitsubishi announced its withdrawal from Normal.
1995
Rename the operation Mitsubishi Motor Manufacturing of AmericaStrategyBackground
After Mitsubishi had taken control of the venture, the joint-venture identity no longer reflected the facility's ownership structure.
Action taken
The company officially changed its name on July 1, 1995.
Aftermath
Diamond-Star Motors ceased to be the facility's official corporate name, although DSM remained a durable enthusiast term for associated vehicles and their shared platform.
1991
Mitsubishi purchases Chrysler's joint-venture interestM&ABackground
The original venture operated as an equal partnership, but Mitsubishi ultimately sought direct control of the manufacturing operation.
Action taken
Mitsubishi acquired Chrysler's interest. Chrysler-branded production continued through contractual arrangements rather than shared equity ownership.
Aftermath
The plant remained a production source for vehicles associated with both companies, while Mitsubishi controlled the operation. Chrysler's equity position was fully sold to Mitsubishi by 1993.
1985
Create a domestic Chrysler–Mitsubishi manufacturing ventureStrategyBackground
Chrysler relied on Mitsubishi imports while Mitsubishi sought greater direct access to the United States. Import restrictions, dealership ambitions, and the strategic value of local production encouraged the companies to establish a shared American factory.
Action taken
The companies incorporated Diamond-Star Motors and selected Normal, Illinois, for a high-capacity automobile assembly plant.
Aftermath
The project created a major manufacturing base and enabled production of jointly engineered vehicles under several Chrysler and Mitsubishi brands.
Reported public incentive package. $274 million (1985–1986)
Sources1 sources
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