I took out my old battery on the highway and replaced it .when I went to start it I lost my radio and dash lights.
You must have shorted something in your vehicle while the battery replacement was done. Check your fuses for the radio and dashlights. Both inside and outside the car.
If it’s not working you have to do a bit more troubleshooting, if that’s the case, let us know and we will help you out!
You need to read this first.
http://www.aa1car.com/library/battery_disconnect_problems.htm
Then contact the dealer to see if any of it applies to your vehicle.
Tester