DETROIT, Michigan - The US government has expanded an investigation into fires that can start in the doors of several Toyota models.The investigation now includes 1.4 million cars and SUVs from the 2007 to 2009 model years. When the probe began in February, 2012 it involved more than 800 000 Camrys and RAV4 SUVs from the 2007 model year.The US’s National Highway Traffic Safety Administration (NHTSA) said on its website that the vehicles were built from September, 2006 through August, 2008.TOYOTA, GM IN THE SPOTLIGHTSo far, Toyota and the government have received 161 complaints of fires involving the vehicles. Nine people have been hurt, according to government documents.All the vehicles use the same power window switch in the driver's door that can overheat and cause fires, the US government said.Leo Kok, Toyota SA’s corporate communications manager, told Wheels24 that five models are under investigation in the US but couldn’t say, if investigators find a problem, how many cars will be affected. “Toyota Motor Corporation is giving the NHTSA investigators its full support. At the moment, it is out of our hands,” Kok said, adding he could not say when the investigation would be concluded. Federal safety regulators also are investigating a similar fire problem in the doors of 2006 and 2007 Chevrolet TrailBlazer SUVs made by General Motors. The TrailBlazer (in the US) was discontinued in 2009 and the SUVs are not being recalled.The Toyota and GM problems appear to be unrelated. The companies got their power window switches from different parts suppliers, NHTSA said.The latest generation Chevrolet Trailblazer will be launched in South Africa later in 2012.