A vehicle exhaust system includes a mixer assembly for a vehicle exhaust system. The mixer assembly includes a mixer housing that defines an internal cavity and which includes at least one injection opening. A manifold is positioned within the internal cavity at the injection opening. A primary injector is configured to inject fluid through the injection opening and into the internal cavity, and at least one secondary injector, which is separate from the primary injector, is configured to inject fluid into the internal cavity when operating temperatures fall below a predetermined level.