Hi, folks,
I got 05 Suburban.
From the purchase of this used one, I have been with a strange noise inside of the blower motor box.

The symptom is: Whenever the engine turns on the noise starts immediately not that loud but like click,click...and disappeared when key off. just all the time while engine on regardless of stop or running.

The A/C and heater blowing is very good. So, once I considered replacing the blower motor, but I am not sure and here questioning.

Does anyone have same noise inside the blower motor box?

 

We had a similar noise, it was a motor associated with the dampers/vent mechanics

 

I replaced the actuator controlling the door of cold/hot shift and the noise disappeared.
Thanks for the answer.