By default, the DrawGridLines property is True. The grid lines are shown in the chart area only, if the DrawGridLines property is True and the DrawGridLines property of the Chart object is not exNoLines or exHLines. Use the DrawTickLines property to specify whether the tick lines are shown in the unit's header. The GridLineStyle property specifies the style to shown the vertical gridlines inside the time-scale unit. The GridLineColor property specifies the color for grid lines being shown in the chart area for specified unit. The BackColorChart property specifies the unit's background color being shown in the chart ( not in the header ).

The following screen shot shows the grid lines in red: