According to GM's filings with the National Highway Travel Safety Administration, the automaker and supplier added a shorter, tenser spring to the switch in 2007 to prevent them from being twisted so easily. However, because the part number was never changed it would be difficult for dealers to know if they had older, faulty ignition switches in their inventory.
GM and Delphi both told Automotive News that the switches were only supplied to the automaker. They don't believe that any of them were sold to parts dealers at this time. There have also been no reported cases of drivers having defective switches installed in their vehicles, and the part subsequently failing. Although, NHTSA has received one complaint on its website from a driver worrying that a 2009 repair could have used the defective part.
According to GM spokesperson Jim Cain, the investigation into the replacement parts came at the request of NHTSA. The company knows about the issue is "cooperating fully with NHTSA," Cain said.
GM will begin repairing recalled vehicles around April 7 with new parts supplied by Delphi, but doesn't expect to have the process completed until October. Congressional hearings into the recall will be held on April 1-2, and the automaker owes its questionnaire to NHTSA on April 3.