Blend door problem..?

KR1STO · 07-06-2010, 01:07 PM

Ok just a quick one, and yes i've done a search..
does this sound like a blend door problem..

When i set the Climate control to say 25C only cold air will blow..
at 16C only cold air will blow, but, at 30-32C HOT air will blow..

now at 29.5C it goes back to cold air..?

I have ran the diagnostics check on the climate control and it has come up with no error codes...?

i don't wanna have to pull the dash out only to find its NOT the blend door...

Any ideas peoples..?

cheers
kris

KR1STO · 07-06-2010, 01:43 PM

ok.. a few other things guys..
i ran the diagnostics on the cc unit and it seems at 16cto 30c the blend door movement is 0% yet at 31C its around 40% movement and at 32C its 100%..

thats the figures from the diagnostic check on the climate control...?

is the blend door stuffed or sticking...?

cheers

MAD · 07-06-2010, 03:01 PM

I havent heard of this problem before. I'd imagine if the blend door was operating, then there is no problem with it. But since it is operating in a strange manner maybe one of the inputs to the system is not functioning correctly.
In diagnostic what does it say that ambient and cabin temperature are? Also what does the sun load sensor say?

KR1STO · 07-06-2010, 03:08 PM

ambient was reading around the 20 mark.. obviously not 20 degrees outside, but the car had been sitting idling for a while..
cabin temp started out at 24 degrees, i then put the AC on and angled my hand in front of it to get air to pass by it and it went down to 18 degrees.. so it looks like its working..
the sun load i didn't full understand but it was around 88-90...
what is the sun load sensor..?

it only seems to blow out hot air at 32C... although i can hear the blend door moving behind the dash...
kind of a creaking sound..

thanks mate..

MAD · 07-06-2010, 03:18 PM

The sun load sensor is there so the system can work out what sort of heat input is being added to the cabin through the windows. In the EF/L its a little white dome on the top of the dashboard near the windscreen.
I dont know which way the reading goes, but you could try putting your hand over it to see if it changes with more/less sun.

Also, check here for more info on the C/C system
http://www.fordmods.com/documents.php?d=9

KR1STO · 07-06-2010, 03:24 PM

cool...
thanks for that mate..
yeah, i went through that link..

it's annoying the crap outta me..haha
cheers

**aussiblue** · 07-06-2010, 03:49 PM

Check the sniffer motor which uses a miniature fan and duct to sample the cabin air temperature. The Sniffer motor fan may have failed, the sniffer fan duct may be broken or disconnected or the sniffer inlet grill blocked. Make sure you don't clean the sniffer grill (to left of clock) with a vacuum cleaner or you will spin the sniffer fan so fast it dies.

Bung your ear against the grill or better a small piece of tubing with the other end in your ear, and you should just be able to hear the tiny fan spinning.

KR1STO · 07-06-2010, 03:55 PM

sniffer motor...?
never heard of that one..!
what does that one do...?
is it not just a cabin temp sensor..?

also, could it be anything to do with the heater tap..?

is there any reason why it says in the diagnostics to check it at 30C and not 32C..?

GS608 · 07-06-2010, 04:24 PM

Hmm, my A/C has been playing up a bit but i can't seem to get into diagnostics mode at all..tried so many times, is there a trick to it?

KR1STO · 07-06-2010, 04:29 PM

hold MODE A/C and AUTO at the same time and it takes you into diagnostic mode...

GS608 · 07-06-2010, 04:33 PM

Yeah tried that many times. Oh well

KR1STO · 07-06-2010, 04:36 PM

have you tried holding them all together then letting go of MODE and A/C together then AUTO..?

GS608 · 07-06-2010, 04:41 PM

Yeah I followed the instructions on Ford mods, then tried a few other combos and it just doesn't seem to work, I did notice that only one of the buttons would register when i pressed MODE and the A/C together, dunno if that's normal or not.

KR1STO · 07-06-2010, 04:42 PM

one more question..
and it's gonna sound like a big noob one but....
what do the Thermostat and the heater tap do EXACTLY..??
now, i know what they do themselves, i just wanna know what exactly they do for the heating...?

i'm thinking of changing my thermostat and heater tap first...

**aussiblue** · 07-06-2010, 04:44 PM

OK checked the sniffer motor was dropped from ED onward instead engine vacuum is used to draw air through that grill. Regardless of system used test as follows, from the factory manual: "To check the operation of the vacuum line, hold a light piece of paper (tissue/business card) over the cabin sensor opening [grill to left of clock] while the engine is running. The paper should be drawn against the panel. "

The manual also notes if the cabin temperature has progressively got colder over time the grill may be blocked, the vaccum line kinked or disconnected or filter at the end of the corrugated inlet tube behind the grill may be blocked with dust.

KR1STO · 07-06-2010, 04:47 PM

right.. thanks for that mate..
it seems to be functioning right...
vacuum is drawing air through the tube..
no kinks and seems to have quite a strong force..
in the diagnostics mode the cabin temp does change...
if that was shorted it wouldn't register at all would it...?

MAD · 07-06-2010, 04:55 PM

The heater tap controls the flow of water through the heater core, on hot setting the tap is open, on cold setting it is closed.
The only reason to change the thermostat to help the heating would be if your engine is not getting up to normal operating temp (90 odd degrees)

KR1STO · 07-06-2010, 05:47 PM

ok.. so it sounds like both of them are working fine then..
eng temp is 90 and obviously letting hot watter through if it heating the car when on 32 degrees..

what gets me is..
why is there heat ONLY coming out when its set to FULL heat..
half a degree under and it cools dramatically...!

MAD · 07-06-2010, 06:02 PM

Did the sun load sensor change with your hand over it?

KR1STO · 07-06-2010, 06:04 PM

it did seem to....
what is it normally supposed to read...?
it seems as if everything is functioning...?

KR1STO · 07-06-2010, 06:05 PM

would the sun load sensor react differently at night as well...?

MAD · 07-06-2010, 06:53 PM

Dunno, what it's normally supposed to read.
It was just an idea, because if it was faulty it may have been 'sensing' a heavy sun load and the C/C unit would think it doesnt need to add heat from the heater core.

As you say, everything seems to be functioning. It seems to be pointing toward the blend door motor. Though I have only ever heard of them failing totally, not like you are experiencing so it might be worth trying a few more things before resorting to taking the dash out.

Have you done the 'mode' and 'off' self test?

KR1STO · 07-06-2010, 07:10 PM

yeah i did that test too and not experiencing any fault codes...
it's got me stumped...!

**aussiblue** · 07-06-2010, 07:35 PM

I'd try checking or replacing the heater tap first. They can fail in a number of ways including the flap that pivots inside inside coming loose on the axle it's fixed to and distorting so it does not fully open. Disconnect the vacuum hose from the tap and see if the lever that opens and closes the tap moves freely but stops at its extremes (i.e the flap has not come loose inside) them use a infra red thermometer to see if the hose temperature cabin side changes as you swing the lever to progressively open the tap more with the engine at normal operating temperature. If the flap is distorted it may only be opening when the tap is fully open. Also try watching the tap as someone changes the climate control tempertaure settings (engine running) to see if the vaccuum is progressively opening the tap more as you increase the temperature setting.

KR1STO · 07-06-2010, 07:38 PM

thanks mate..
will do...
i'll do thermostat and heater tap and may as well do a coolant flush while i'm there..
will let you all know if that solves the problem..

thanks heaps everyone...

blackers10 · 07-06-2010, 08:10 PM

the montys mum had the thermostat die and it wouldn't heat the water in the heater system so its a good idea to change that

i found my heater would heat soak the air in the climate control system if i turned the fan to the OFF position but then when i cranked it up again it would blow the hot air then go cold/room temp

i would say my blend door died

KR1STO · 07-06-2010, 08:14 PM

yeah this is sort of just room or cabin temp air until you put it up to 32C..
i've got a new thermostat in the garage and i'll change the heater tap too...

as i move the temp up and down in diagnostics mode, it shows the blend door moving..
so i'll try the simple stuff first..

thanks bud

MAD · 09-06-2010, 12:36 PM

Quote:

Originally Posted by blackers10

i found my heater would heat soak the air in the climate control system if i turned the fan to the OFF position but then when i cranked it up again it would blow the hot air then go cold/room temp

i would say my blend door died

My old XF used to do that. I had a small leak in my radiator and if I left it too long between top-ups water would stop flowing properly though the heater. Pretty sure it was an air lock in one of the heater pipes as the engine never overheated, and the gas converter always had flow. Generally about 20mins into the drive it would start to flow again.

Any luck yet KR1STO? Keen to see what this turns out to be.

KR1STO · 09-06-2010, 02:50 PM

no luck yet mate..
but, engine and gearbox are coming out of the car to make way for a V8 so if it's not working properly after that then i'd say it's a blend door prob...