TD4 idle affected by temp control but a/c off.

Driving my TD4 yesterday I noiced that there was a slight vibration at idle which went when I turned the temperature control down to the coldest setting. The air con was off so I am at a loss as to why this should happen.

I have noticed that when I do switch the aircon on the light comes on on the switch but engine revs do not change and I dont here any 'click' to suggest anything has switched on (although not familiar with this car so not sure what to listen for).

Its too cold to get an idea of whether or not the ac is working but I am wondering if someone has wired it permanently on or wether this is a common fault??

Aircon is on when the heater controls are set to screen even though the light is out. Vibration could be from the aircon fan front of engine.

No audible click or change in revs when you switch on AC is normal.

You need to have your head under the bonnet and someone else flick the switch to see /hear it engage.

SV.

I will check, cheers for that.

take into account IF there's a ptc heater .. standard on '04 / '06 ..

( http://www.landyzone.co.uk/lz/f69/2004-freelander-1-sales-brochure-specification-197513.html )

with heater fan 'on' and temp dial above the 1-o-clock .. ptc is 'on' ..
( there's an audible clik from the ptc switch on the temp control dial )

that effects idle rpm ..
i.e ptc 'on' will raise idle rpm slightly .. 'off' .. and idle rpm backs down ..

what actualy happens .. when ptc is switched on .. idle rpm will at first drop for a second
.. then pick back up to slightly above regular idle ..

( if it's been 'on' .. then turned 'off' there will be a corresponding change to idle rpm )

the ptc consists of 3 electrical heated elements .. raised idle compensates for current draw

Interesting..never had one of these before, certainly describes the behavior of the engine, will check it out. Thanks.

I'm having the same issue did you resolve it??