Each group vehicle insurance policy shall provide that the policy, the application of the employer, or executive officer or trustee of any association, and the individual applications, if any, of the employees, members or employees of members insured shall constitute the entire contract between the parties, and that all statements made by the employer, or the executive officer or trustee, or by the individual employees, members or employees of members shall, in the absence of fraud, be deemed representations and not warranties, and that no such statement shall be used in defense to a claim under the policy, unless it is contained in a written application.
215 ILCS 5/388c