Blower fan whistle

[NevilleT]

My blower fan whistles on low and medium speeds but not high speed. Does not matter if A/C is on or not. I have tried two second hand replacements and have the same problem. Tried all the obvious things like air leaks and something stuck in the housing but no success. The most recent one I tried on the floor with jumper leads to the switch and the problem is still there. It has me beaten at the moment and I can find no mention of a similar problem anywhere on the Internet. Can anyone help?

[NevilleT]

Found the problem. It is the controller module. I tried two second hand units before I found one that fixed the problem. If anyone is interested, check out https://www.motor.com/magazine-summary/foreign-service-aug-2012/

[ilv1004s]

also new units can be had for pretty cheap