Hi,

Need some advice - this afternoon when I was driving back home, I heard a rapid periodic (something like 2 times per sec) clunking/knocking sound coming from the passenger side. After few minutes it stopped, but since then it comes back at every 5 mins or so. It looks like it is linked to the aircon because:

1. As soon as I increase A/C temp by few degree, the noise stops. If I reduce the temp, the noise comes back immediately and stays there even if I turn the aircon off. If I turn my car off and put car key back to the ignition without actually turning the car on, the noise returns.

2. Rapid periodic noise does not vary with fan speed, engine rpm or any other thing. It simply keeps clunking which sounds to me something more like a plastic pulley with teeth trying to engage against something, but missing.

3. I can touch and feel the clunking vibration coming from somewhere behind the cigar lighter passenger side. It is certainly not from somewhere under the hood as I can't hear anything when I open the hood.

4. It is a Magna TJ 03 with climate control and everything including Aircon works fine apart from that annoying knocking sound.

Please help - need your advice. Thanks in advance.

It is the temp control motor under your heater box, if you pull out your console top and your compartment in the centre you will see it here. Is becoming a common issue as these cars get older and is a prick to change as well

It is the temp control motor under your heater box, if you pull out your console top and your compartment in the centre you will see it here. Is becoming a common issue as these cars get older and is a prick to change as well

:( not looking good. PM sent with a request for a unit if in stock. Roughly how much am I looking at to get it fitted by a mechanic?

It is the temp control motor under your heater box, if you pull out your console top and your compartment in the centre you will see it here. Is becoming a common issue as these cars get older and is a prick to change as well

If it is the temp control motor/servo then this is how it looks from under the passenger foot well:

http://i923.photobucket.com/albums/ad78/the_ash_1/DSCF17331.jpg

To get to it you will need to remove your glove box & surround, along with the tray underneath the glove box. You will also probably need to pull out your centre console and the pieces that surround it - including the lower part of the dash which clips into the carpet. Bit of work involved but nothing that you can't do yourself. Just take extra care with removing pieces to not break or scratch them - if you need to use a screwdriver then put a rag over it otherwise use plastic levers (if possible) - in the past I've used plastic bike tyre levers to get some pieces out of the dash.