Funny noise in dash

[Whitaker717]

Back to another episode of what the hell is that noise. As soon as I start the Comanche something behind the glove box makes this loud squeaking sound like a flap opening or closing. Makes the same sound when I turn in the fan from say defog to vent. Every time I start it, it makes that noise. Why would that be?

[watchamakalit]

One of the blend doors in the heater box could use some lube I would say.

[ghetdjc320]

Agreed. Probably the large vent door near the passenger kick panel area. 

[Whitaker717]

How do I get to it? Do I have to take the dash apart?

[ghetdjc320]

3 minutes ago, Whitaker717 said:

How do I get to it? Do I have to take the dash apart?

Negative, it’s under the passenger side behind a small plastic trim piece. Nothing really needs to be removed to see if. There are some little vacuum motors that move all the different doors for the hvac system. Probably just need some oil on the joints and linkage 

[Whitaker717]

Thanks as usual! I will take a look tomorrow 

[schardein]

Yep there is a vacuum operated flap as others have said.  I've noticed in my XJ that if I shut off the engine and sit for about 5 minutes, the vacuum bleeds off enough to allow that door to either open or close, whichever way it is spring loaded.  I clearly hear it.