Originally Posted by MC5Wes
If your car is operating ok. Not overheating.
You probably have a problem with the air control servos. There are two of them. One for temp mixing and one for outside air.
If you look at the links I posted above. You will see pictures and a Do It Yourself thread.
All of the Lexus models use the same servos. I tried to fix mine in my RX300. But the problem came back. So I eneded up just changing both.
Back in 2011 my problem was resolved by replacing a leaking radiator. Lately I have been hearing a clicking sound while driving, puzzled as nothing seemed off until the past couple of weeks. Very brief minute of heat even when set on HIGH and then turns to cold air. Checked out your above link to Servos and I see you mention a clicking sound... How confident should I be that it's the servos and any chance they can just be adjusted or should they be replaced (or just one of them and if so - which one)? Thanks