Ive got a 72 velle Dash in my car and ive got the behind dash wiring harness too, I dont have the seat belt wiring harness, whats going to happen with the buzzer and the light on the dash for the seat belts?

Leave th e buzzer disconnected and leave the belt light out secure wires up & outta the way No Big Thing

72 under dash harness will not work with 70 engine harness. Many differences in the bulkhead connector.