This example turns on high-low lines for chart group one in Chart1 and then sets their line style, weight, and color. The example should be run on a 2-D line chart that has three series of stock-quote-like data (high-low-close).
With Charts("Chart1").ChartGroups(1)
.HasHiLoLines = True
With .HiLoLines.Border
.LineStyle = xlThin
.Weight = xlMedium
.ColorIndex = 3
End With
End With