General Motors made a fateful choice in the fall of 2001.  The company considered two options for ignition switches to be installed on the 2003 Saturn Ion. One drawing submitted that September contained an ignition switch that included a longer detent spring and plunger with greater torque.

In October, one month later, the company considered another engineering drawing that showed a shorter detent spring and plunger, which made it easier for the switch to move between the “run” and “accessory” positions.

Documents do not shed light on what motivated the decision to eschew use of the first switch, but GM’s decision to go with the shorter switch has proven to have far-reaching consequences. The shorter switches have been linked to at least 32 car accidents resulting in at least 13 deaths.

Drawings of the two different switches were among the 200,000 pages of documents GM submitted to federal investigators who want to know why the company waited until this February to recall more than 2.5 million cars afflicted with the defective switches when it had knowledge of its flaws for more than a decade. The springs in the shorter switches were 9.6 millimeters; the springs in the longer ones were 12.3 millimeters, according to the documents. The difference between life and death was 2.7 millimeters.

On Wednesday, the Center for Auto Safety, which first noted the differences between the drawings, sent a letter to General Motors CEO Mary Barra, asking if she had been briefed about the differences in the parts – and the documents that illustrate them – in advance of Congressional hearings held earlier this month. Clarence Ditlow, the executive director of CAS, and Joan Claybrook, a former head of the National Highway Traffic Safety Administration, called on Barra to release all documents that shed light on the decision to select the switch utilizing the shorter detent spring and plunger.