Dynamic Layer and Simple Renderer not working

[NigelAlford]

I've been having a tough time getting the renderer to work with my dynamic services all internal but ending with: '/MapServer/0'.  My map is built on a series of loops and callbacks, everything is working except for trying to show a dynamic layer with the esri renderer.  Does anything look wrong here?  I've thrown everything in an object to ensure nothing is getting overwritten during execution.

Thanks,

var setDynamicLayer = function(URL, img, lyrNm, mxSc) {
        lyrHldr.push(new esri.layers.ArcGISDynamicMapServiceLayer(URL, {
            id: lyrNm
        }));
        var Ren = {};
        Ren.defaultSym = new esri.symbol.SimpleMarkerSymbol(esri.symbol.SimpleMarkerSymbol.STYLE_CIRCLE, 30,
           new esri.symbol.SimpleLineSymbol(esri.symbol.SimpleLineSymbol.STYLE_SOLID,
           new dojo.Color([100,149,237]), 1),
           new dojo.Color([224,255,255,0.75]));
        Ren.renderer = new esri.renderer.SimpleRenderer(Ren.defaultSym);
        Ren.options = [], Ren.drawingOptions = new esri.layers.LayerDrawingOptions();
        Ren.drawingOptions.renderer = Ren.renderer;
        Ren.options.push(Ren.drawingOptions);
        _.last(lyrHldr).setLayerDrawingOptions(Ren.options);
        return _.last(lyrHldr);
    };