Hi there, first post! I have returned to the Focus fold after killing both my cars in 1 day! I have bought a 52 plate 1.8 tdci ghia estate to get me by. Now I had one of these 3 years ago and loved it so when one was going cheap and I was in need I jumped at it.

The only problem I have and is common to both of the 1.8 tdci ghia’s I have had is the digital cabin heating. Mine has the digital display with the blue and red buttons to change the heat. Now when the car starts up the engine warms up as normal and the heating works…..22 degrees gives warm air through the vents. After a while the air goes cold unless I put the display up to Hi and then it gives hot air. Turn it down to 28 degrees and its stone cold. It sometimes goes cold when I go fast but not always, it sometimes goes cold when I’m doing 30 mph. There is no clear pattern, just random cold then hot air. My wife likes the car warm so when we travel together I’m sitting there sweating with it set to Hi or she’s sat there freezing with it set to any other temperature. As I said both of the focus ghia’s I’ve had did this.

So I’m thinking maybe thermostat or the mixer flap. I’m guessing these are controlled with actuators so not quite as simple as a wire on the back of a dial! With the lack of consistancy; i.e. its not cold on all settings I’m thinking it isn’t the matrix.

I have googled this as I thought it may have been a common fault but haven’t found anything for the digital controlled version.

Any help would be very much appreciated

There is probably a faulty climate sensor somewhere.

I know on the MK2/MK2.5 cars with climate control there are a couple of sensors (one to monitor cabin temp and one to monitor ambient heat loading through the windscreen).

Would your car have a similar set up?

For info have a read of this, it may help-

http://www.justanswer.com/uk-ford/2ljkp-hi-my-st220-56-climate-control-does-not-seem-work.html

Clive's spot on (10pts to Clive, no confering) that there are two sensors for climate control :-

1. Sunload sensor - that's the small dome (like R2D2's head) poking up from the middle of dashboard just behind the windscreen. Mine appears to be a semi-translucent dull red when a bright light is shone from behind.
   When I had the radio out (it was U/S) I don't recall seeing any wiring heading in that direction, but the top dash pocket may have been blocking the view.
   
2. Cabin temperature sensor - located behind the small grill that's between the heated front and rear screen switches.
   If you remove the switch panel then you'll see the grill is an opening for a small tube with a funnel shaped end(attached to the switch panel) that directs cabin air onto the temperature sensor which is clipped into recessed support bracket (looks a bit like the CND logo) about 6cm back from the front face of the switch panel.

Wow thank you for the replies.

Mine is a mk1.5 so doesn't have the sunload sensor.....or at least I can't see one on the dash. I do indeed have wee grill next to the front and rear screen heater switches. I found some diagnostic routine online where you press the off and footwell buttons and then the auto buttom and it went through but didnt show any faults.

So does anybody know where I can get a new sensor from (other than Ford)? Or even what I would search for....part number, proper name?

Thanks again

Is this the sort of thing I'm after?

http://www.ebay.co.uk/itm/FORD-MONDEO-FOCUS-FIESTA-COUGAR-INTERIOR-CLIMATE-CONTROL-TEMPERATURE-SENSOR-/281148380457?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item4175bfd529

Does appear to be about right.

Just thinking about this......doesn't the climate sensor monitor the cabin temperature? I never have the a/c on so would there not be another temperature sensor monitoring the air coming out of the mixer flap? Or does the climate sensor do both?.......might be talking complete rubbish here!!!