My Rx330, manufactured in 2004, has developed an air conditioning fault in that it initially blows cold air but after a few miles no longer blows cold. The a/c diagnostics gives a 24 code but the a/c light switch remains constant on, not flashing. A few days ago, there was a clicking noise which seemed to be coming from under the dashboard maybe at the passenger side. I took out the a/c air filter and cleaned it but the noise remained. Anyone any ideas what my problem is.