I am trying to apply a graduated color symbology from one layer to another. The script adds a layer to an mxd but foes not apply the symbology from the symbology layer. Can someone tell me what I am doing wrong? 

This did work a few days ago for other layers but is no longer working...

This is the script, path names modifiied

>import arcpy

>arcpy.env.workspace = r"C:\Workarea\BrandiS"

>mxd = arcpy.mapping.MapDocument(r"C:\Workarea\BrandiS\SymbolTest.mxd")
>df = arcpy.mapping.ListDataFrames(mxd, "Layers")[0]

>featureLayer = r"C:\Workarea\BrandiS\TestLayer.lyr"

>addLayer = arcpy.mapping.Layer(featureLayer)
>arcpy.mapping.AddLayer(df, addLayer, "TOP")

>if addLayer.symbologyType == "GRADUATED_COLOR":<br>
>>   addLayer.symbology.valueField = "Join_Count"

>symbolLayer = r"C:\Workarea\BrandiS\SymbolLayer.lyr"

>arcpy.mapping.UpdateLayer(df, addLayer, symbolLayer)

>mxd.save()

>del mxd, df, featureLayer, addLayer, symbolLayer