Because Chevrolet is a subsidiary of General Motors, it doesn't have a president. Instead, if you want to reach a high-ranking official of the auto manufacturer you'll need to contact one of GM's executives. As of December 2014, Mary Barra is the chief executive of General Motors and Dan Ammann is the president. You can contact the president via a letter through the mail or by online submission.
Address the letter to the attention of the current GM president. Correspondence should be sent to General Motors Company, P.O. Box 33170, Detroit, Michigan 48232.
Chevrolet's website contains a submission form for inquiries and concerns. Include the president's name in the body of the text. Fields are also available to include your name, email address, phone number and preferred method of contact. A chat feature is also available on the site, so you can ask that your concerns be sent to the president via a customer representative.