The headlamp designs of today and the future will be increasingly complex to match the increasingly dramatic vehicle designs. These complex shapes require lamps that are vented to relieve pressure and thermal stresses. Specifying headlamp vent locations to optimize humidity clearing while minimizing dust intrusion is often a trial and error process requiring several iterations using prototypes. Computational Fluid Dynamics external flow simulations can provide an accurate view of the lamp external air flow and pressure gradients which allows the designer to specify vent locations for maximum air exchange. CFD can thus reduce the need for prototyping and testing while reducing cost.