70 Cuda High Beam not working

Hi Everyone
New to the forum with a recently purchased 70 Cuda FE5 Red 340 and wanted to ask for help regarding a high beam problem. When I flip the light switch on the dash up fully the parking and head lights go on fine. When I press the high beam switch ‘on’ using the floor switch then the headlights go out completely, but, parking lights stay on. If I press the high beam floor switch again then the headlight come back on fine.

Thanks in advance for any thoughts or ideas !
Author: 70CudaFE5