Odd question, but for the past three months, I've been getting a 'squeaking' sound from underneath the passenger dash area. It'* not your typical motion-related dash squeak from plastic-on-plastic--I had the car in the garage last night with the key to 'ON' (motor not running) and it was still doing it. Does it with the A/C on or off. I'm wondering if it'* vacuum-related? It sqeaks and then makes a 'releasing' type of sound. I can record if necessary. Quite annoying! It occurs every 15-30 seconds.

Thanks.

Blower motor maybe?

Ya know, that'* a good thought. That'* the correct area and it does sound vacuum-related. Would it still be doing that though with the HVAC system completely off?

It could be piece that seals inside/outside air mix for recirculation or outside air. Mine only squeaks a little when it goes either to inside or outside. And it'* really not a squeak just a rubber on plastic noise.

The mix for air intake to the blower motor is half open to inside and outside (atleast on the auto climate control), then when you push inside or outside air on the control, then the "bowl like" plastic piece seals off the other intake. That seal could be the noise, but why is it doing it every 15-30 seconds.... good question..