Hi everyone, I have a 2001 cl. If I put the car in reverse without the a/c system on it doesn't make a noise, but if I put it in reverse when it's on I hear a rattling sound coming from the vents. If you're familiar with when computer fans go bad and they also make a rattling sound, that's what I'm experiencing. I don't understand why it only happens when I'm in reverse, even if I'm not moving. Any ideas on what needs to be fixed/replaced? Thanks for any input.

 

check the power steering return line on the front subframe its under the a/c pulley ,if its not in its holders it rubs when the engine shifts into reverse