My car just started making a new noise this week. Its an 04 TSX with 109K on it. I have never had an A/C problem with it. On the passenger side there is a rattle noise that only happens with the cold air blowing, this is with or without the A/C being on. But when I turn the heat on the noise goes away. I have cleaned the cabin filter so I know it isnt anything stuck in that. It more sounds like its coming from the mid dash area. Everything still works fine with the air. It isnt a humming noise as I have read about blower motors. Its only while the car is sitting still that I notice it. Its a pulsing constant rattle that stops when something kicks off from that area. But when it kicks back on the noise starts again. Im a female and trying to explain this the best I can I dont know much about cars. Please help!

 

Unfortunately, I don't know the answer to your problem. But...I just wanted to say that just because you're female doesn't mean you can't handle car stuff!

 

I actually have a similar noise but it's independent of the HVAC being on/off. In my case, however, I believe it to be caused by some rogue shards of glass which ended up in my A/C vents when my car was broken into a couple of years ago. I never managed to get all of it out. Was your car ever broken into?