You must pay vehicle repairs out-of-pocket I you have liability-only coverage. A liability-only policy does not pay for damage to your car. The policy must have physical damage coverage to make a claim for deer-related damage to your car. Illinois law does not require physical damage insurance, but lenders typically demand it. Crash-related injuries may be covered by the medical payments portion of the policy.
Physical damage insurance is split between comprehensive and collision coverage. Comprehensive pays for damage caused by events like theft, vandalism, hail, fire, an deer. Collision pays for damage caused by an accident with another car or fixed object. Both typically have deductibles.
Details surrounding the deer accident determine if the damages are paid through the comprehensive or collision portion of the policy. There must be actual impact with the deer for a comprehensive claim. It is a collision claim if you swerve to avoid the deer and end up hitting a tree or fixed object.
Keep in mind tat it is better to hit a deer than swerve to avoid one. Swerving at cause you to lose control of the car. Rolling the vehicle, hitting a tree, or crashing into an oncoming car will cause serious vehicle damage and injuries are likely. It is much safer to brake firmly, stay in your lane, brace for impact, and come to a controlled stop.