does anyone know how or what to repair inside the instrument cluster when your brake light on the dash is in and stays on?

 

What makes you think it's the cluster at fault?

 

Well-said. The light is on for a reason. It's not just to let you know that the parking brake is on.

You can verify the parking brake switch isn't faulty by disconnecting it. If the light remains, there is another fault.

Generally speaking, the instrument cluster doesn't tell the brake light to stay on - it does what it's told.