heater box noise at idle

i have searched and havent found anything to answer my question. i ahve a 94 xj 4.0aw/auto, the issue i have is when the a/c is on in any position max/norm/bilevel when i come to stop there is a screaching noise coming from the heaterbox at the passengers feet, doesnt do it all the time any suggestions would help, i have checked all the vacumn lines and connections and have not found any leaks the a/c and heater work fine thanks in advance for any input

The blower motor will make a screaching noise when its worn out.

i have checked the blower motor,and the cage, it makes this noise when the fan is unplugged, the noise is coming from the heater box below the glove box, am going to take it out this weekend and check it out thanks