Heat/AC Controls

This morning when I was warming up my car, I turn the heat/AC switch from blue to red. When I did that I heard some noise like something was opening, but when I turned it back to the blue it didn'tr make any noise at all. Then I turned it back and it made the same noise. I am trying to figure out why it is making that noise.

This morning when I was warming up my car, I turn the heat/AC switch from blue to red. When I did that I heard some noise like something was opening, but when I turned it back to the blue it didn'tr make any noise at all. Then I turned it back and it made the same noise. I am trying to figure out why it is making that noise.

I have a 97" Pontiac Grand Prix with a 152,000 miles on it.

I have a 97" Pontiac Grand Prix with a 152,000 miles on it.

I believe the duct control is spring loaded on one side. The engine vaccume power pulls the ducts from cool to heat and the spring pulls it back from heat to cold, or maybe its hte other way around. Either way, I have a 91 regal and a 03 gp gt and they both make hte sound so I wouldnt worry unless you hear something screaming in pain from inside.

I believe the duct control is spring loaded on one side. The engine vaccume power pulls the ducts from cool to heat and the spring pulls it back from heat to cold, or maybe its hte other way around. Either way, I have a 91 regal and a 03 gp gt and they both make hte sound so I wouldnt worry unless you hear something screaming in pain from inside.

cool, okay