How do the two ingredients in hydrochlorothiazide + losartan work to lower blood pressure?

In Cozaar-Comp, losartan blocks angiotensin II at AT₁ receptors, inhibiting blood-vessel constriction and aldosterone release, while hydrochlorothiazide increases sodium and chloride excretion and reduces plasma volume, although its blood-pressure-lowering mechanism is not fully known; together, they lower blood pressure more than either alone.