Hope you have the problem fixed, but if not, here is a place to start. The Voyager monitor has three wires used to automatically switch the camera displayed on the monitor. One wire goes to the backup light circuit; when you shift to reverse, the rear camera is shown. One wire goes to a left turn signal; when you signal a left turn, the left camera is displayed. The third wire goes to the right turn signal.
From your description of the problem, the right turn wire is connected to one of the running lights instead of a turn signal light. Or maybe the ground isn't connected to a dual filament running/turn signal light.
Check to make sure all of your side and rear lights are working correctly. If one isn't working right, get it fixed. That may solve the camera problem.
Good luck.
Steve