Recently replaced my glow plug module, before I replaced it I could hear a buzzing type noise when the GP where heating. Now with this new one it makes no noise, the wait to start light comes on and i can see the Amps moving after. Truck starts fine hasn't been cold, started it this morning was in the 40s. I'm just wondering if i should be hearing a noise when the GP are heating or may something be wrong. GP are around two years old.