How does the D9 Digital Climate Control work?

[BruceT]

Having two of the same car and engine is not healthy


The misses wagon air heats up A LOT quicker then mine.

When I got the car the outside temperature sensor was faulty (Reading 49c etc) Ive replaced this and it works.

But, how does my misses wagon heat the air so much quicker then mine?

Is there more temp sensors in the cabin that are comparing external and internal temps to determine what temperature air to blow out?

I mean, it does get warm... but my misses wagon gets hotter & faster at 30C.

I did read that they have a 'electric' esque heater somewhere? Maybe the fuse for this on my has blown or the system is faulty or could be the inside temp sensors not working correctly so its not blowing out the correct temp air?

[Captain Jack]

There's an internal temp sensor near the light cluster under the aerial, which may be faulty. There's a also a small fan there to, I guess, to direct the air towards the sensor?

With regards to the car heating up quicker, is due to the heater matrix which is somehow electrically assisted. Mine will blow warmer than outside temperature within 30 seconds and is much much quicker than my old D8, which took over 5 mins to get some warm air out of the vents.

Can't be of more help, I am adraid.

[Welly]

I'd check the little sample fan too - Steve Earwig did a sort of how-too I think?

The matrix does have resisters fitted to electrically heat the water because the engines' coolant is so slow to heat up.

The cabin fan, when left in 'Auto' has a vary-speed drive depending on the coolant temp so maybe your coolant is not getting hot quick enough - possibly a duff Thermostat? it wouldn't hurt to do a flush, stat change, and coolant refresh.

[BruceT]

Thanks guys, I will check the interior light sensor/fan.

How do I remove? Any clever tricks or just pull it down carefully?

Yeh mine seems like a D8 in comparison, its takes about 5 mins for it to even start getting warm so makes demisting hard, Im dreading when we get proper ice!

Where is the thermostat on the D9 90HDi?

[Welly]

You could check the hefty old fuses in the engine bay for the 'additional heating' circuit maybe? could be an easy fix, no idea which fuse it'd be in fact I don't think it;s even mentioned in the owners manual at all

Thermostat is right hand side (air box side) upper half of engine with hose attached and a bleed allen-head screw (or tyre valve).

[BruceT]

Cool.

Ill change the thermostat then maybe, coolant change can wait as ill get that done when I get the Timing belt & water pump done within the next 6-8 months.

How I remove the interior light and housing?

I'm at work so dont have tools but it would appear the light pops out with some force and probably some screews/torx bolts holding the housing in?

I can see the small fan in there, when is it suppose to start to spin? I didnt start the engine but was 2 ingitions turns in and nothing.

[Welly]

The little fan coes on with the ignition.

I'm sure there's a how-too post somewhere, in fact I remember that a long-term siezed fan burst back into life after being cleaned

[BruceT]

Come on Welly, get searching for "Small fan/Interior fan" Only joking!

I cant see photobucket images anyway on the work pc but alas something for me to play with at the weekend.

The fan is seized then, so that will not be helping a great deal...


My mission, to see this little fan whiz around!

[Doggy]

I'd check the little sample fan too - Steve Earwig did a sort of how-too I think?

Linky

Have you disabled the EGR on either his or hers 406?

[BruceT]

Both EGR's are connected - Doesnt mean they are working properly though? Unsure of how they can fail either open or closed?

[BruceT]

That light console area is not the same as mine as mine does not have a Sunroof.

Do I have to pop out the light first?

[mjb]

I'm surprised nobody's said the obvious here - get the drivers side of the car on a kerb, brim the coolant expansion tank, and make sure the system's bled - especially on the pipe going through the bulkhead

That light console area is not the same as mine as mine does not have a Sunroof.

Do I have to pop out the light first?

Yes. Lever it from the drivers side

[BruceT]

I managed to clean the fan, but could not remove it fulyl as it was a torx screw head size which im suprised my tool kit did not have.

I still managed to give it a good clean in there and now it spins.

We shall see if this improves things.

MJB.

When you say put the drivers side on the kerb and brim the coolant...

Can you explain futher? Am I checking to see if its full when the drivers side is raised?

Is it supposed to be brimmed and how do I bleed it?

[legoless]

It should be full when all the car is level. If you need to top it up then get the drivers side wheel as high as yoou can ie on a high curb and or jack it up. (Make sure its secure tho This is because the header tank is slightly lower than some of the coolant hoses /pipes in the engine. Raising the wheel makes it the highest part of the system. If you follow the pipework there are some very small bleed valves which you open up and watch as you top up. As the lowest one starts to weep coolant nip it up and watch the next and so on untill you cant get it any more fluid into the header. Put the rad cap on and then drop the car back down to normal.