Changing Color in "Pattern Brush Options"

I just discovered that when you make a pattern brush, the colorization can not be set to "none".  You have to select tints or tints & shades.  Maybe this was obvious to other people, but it took me a while to figure out what was wrong! ---K

Set the colorization mode to Hue Shift.

Use the eyedropper to pick up the key color from the artwork displayed in the tiny tile previews of the modal dialog window, not from the artwork on the page.

JET

In some circumstances there is an easier way if the brush has been applied to a path, select the object the the pattern brush then Go to Edit>Edit Color>ReColor Art and select the color yo want to change and double click its shorter color bar and then slect the color you want from the picker.

That will only change the color on the path in the document but will make a newbrush for you in the brushes panel.

If you want to change the color of the brushe's elements, drag it out of the brushes panel onto the artboard, change the color and drag it in again. In case it is a pattern brush with more than one element, you should read the manual on how to create this stuff.