Unfortunately, there are no magic solutions. But here are a few ideas to protect your vehicle:
1) Put a car cover over your automobile when it is parked to prevent access.
2) Insert the wipers into some PVC pipe for several days. The crows may leave the wipers alone after they get tired of them.
3) Installing an owl effigy nearby may give some temporary respite as crows attack owls, and this may draw their attention away from your vehicle. But be prepared for the noise as crows try to “drive” the owl away.
4) Hazing or other crow control methods may be needed. Be sure to consult with state wildlife agencies before initiating any hazing or control techniques.