How Do I Manually Draw a Line on an Excel Chart?

[DMunoz]

I've created a chart in Excel and have formatted the automatic major / minor grid lines as needed. With the data plotted (scattered), I need to visually show the grid in 4 equal quadrants. The problem is that I need the exact center line for both vertical and horizontal to be different from the other vertical and horizontal lines, such as larger and bold. How can I simply change those two lines without affecting the others?

Thanks in advance for the help.

 

[DMunoz]

I've answered my own question. I finally found the Drawing Tools and simply added the lines. DUH!!!

 

[JVFriederick]

Tip :
If you want a dynamic line that adjusts to changes in Y axis scale, add another range with all the same values, turn off the markers, and make the line big and fat.