Postby tmr_colt » Thu Sep 10, 2009 12:22 pm
I'll 2nd/3rd/4th/5th that.
Easy explanation
Somewhere in the car there's a temp sensor as part of the air con system (like what you'd have at home in your house... or inside your fridge).
You set your air con to a certain temp, so the system will continue to drive the air con until your desired cabin temperature is reached. This is controlled by one of the computers in your car, so it treats everything as either 'yes, within limits' or 'no, outside of limits'.
The clicking you're hearing could be a couple of things.
i. like mentioned it's the air conditioning clutch kicking in/out or
ii. more likely what you're hearing could be a relay for the system continually clicking
The computer 'flicks a switch' (aka relay) on or off whenever the cabin temp sensor reaches the desired temperature or falls outside of the desired temp. (pretty sure I just repeated myself in a different way heh).
The lower you set your in cabin temperature, the harder the entire system works and the more frequent you'll hear these clicking noises. Chances are that you'll never actually achieve the 'lowest' temp setting (just like trying to set your home A/C to 15deg and getting massive power bills).
Myself, I set my car, my house, work to 21deg all the time and it's a pretty good medium.
These noises are normal, hope that helps in some way.