Very Noisy Fan

I recently had my low-pressure tube replaced on my AC, since then my engine fan has run at extremely high speeds when the AC/Heat is running. Unlike previous issues with the fan speed the fan stops running if the AC is turned off, or if still running when the car is turned off.

What is even stranger is that when at a red-light, and my foot on the park brake the fan runs even louder - if I move the shifter from D to P or N the fan speed is lessened.

Any clues? Thanks.