Odd Squeak (seemingly) temperature sensitive...?

[billschroeder5842]

My OCD is always finely tuned and ready at a moments notice.

My latest obsession is that I notice a squeak coming from the passenger side dash area of my 91 at lower speeds, over roads that have a more "wash board" feel. The funny thing is that the noise happens when the car is "colder" especially when first started and the air from the vents is cool.

When the engine heats and I can push 75 degree air through the system, the squeak seems to go away quickly. BTW, the squeak is a high pitched, "back and forth" three times quick and sounds more plastic in nature. Once the car is warm (or on hot days) the squeak is not noticable.

Anyone ever heard of such a thing? Is there some HVAC components that I need to check? Vents, blend doors, electrical wires? Of course I'm planning a disassemble of the dash passenger side as COVID means I have extra time to be crazy.

Thanks!