what do you have in it?
Is it full? Empty?
Mine is pretty full.
I have fan at top, but that is normal position.
I had two temp/hygrometers placed where I could see them, top front and top bottom.
They were so close in temp/humidity I just use one. identical humidity, 1 degree different temp.
I use beads, in two long, narrow trays and have them on the second shelf and third shelf at the left and have the boxes position so that there is an "air chimney" roughly 4" by 4" in the left rear corner to allow for air and moisture movement.
I also calibrated the hygrometers.
If yours is not full, you need to put a bunch of boxes in to stabilize the humidity. Plastic and metal will do nothing to absorb or stabilize.
I have had no issues with humidity. I also probably have twice the recommended amount of beads.