Aux Heater - Runs constantly when ambient is below 13 Degrees

[Fraz-ktf]

Hi.  My Aux Heater runs constantly, regardless of engine temp, on c the outside temp. is below 13 degrees.

is this correct operation?  (I'm guessing not?)

If not, what should I be looking for as the fault please?

[insanitybeard]

Didn't you have some problems with your booster heater backalong? Did you end up repairing your original heater or did you modify an older D5W-Z model to fit?

[Fraz-ktf]

Didn't you have some problems with your booster heater backalong? Did you end up repairing your original heater or did you modify an older D5W-Z model to fit?

Yes, I modified an older model to fit.  there are no VAGCOM errors and the jet engine starts with the car and runs on after you turn off the engine but it does it even after long runs or after the engine is at op. temp. so I'm assuming it's running constantly.

could this be why my MPG has dipped?  The engine still takes a while to get to temp too - certainly not within 2 miles of driving like my friends 130 tdi.

any tips as to the issue?

[Mirez]

It might be normal operation tbh if you drive economically. Dont forget its looking for the external temp to be below around 10*c AND the coolant temp to be below 80*c. With the current weather the first is largely a constant and with the TDI being so efficient on heat you may well be staying at or near to 80*c.

Don't believe the temp guage either, its programmed to sit at 90*c when anywhere from about 75*c to 105*c so you don't see it constantly moving!

[bigdave982]

Id be happy if mine ran☺☺

[Chrispb]

Id be happy if mine ran☺☺

Get under and get it sorted Dave lol

[bigdave982]

Been under it repaired the wire,bypassing plug for thick red and brown cables and a green one the was chaffed. Found one wire that donr go anywhere on the other side of plug so left thatone lol
Bypassed temp switch on wiper arm
Cleared codes again
Tried dosing pump and blower in vagcom, not sure what shouldve happened but nothing did
Gave unit a couple of taps with hammer as read somewhere theres a fan in there that can get stuck
Pretty sure fault codes were flameout
Vagcom says recirc pump off but aux pump under bonnet is when you feel it
Also reports flame temp at around 550Ã,° wh3n not running cant be right!

Pulled my back getting up so off work atm

[MadDog]

Hi,
My heater also runs constantly with outside temp around 10c or below. I read somewhere that once the heater starts it runs at max chat until the coolant temp reaches around 80c and then switches to a lower  setting but won't shut down unless engine is turned off or OAT rises to around 10c or above. (or fault is sensed)
with regards to MPG it shouldn't make any difference to the readout  shown on the instrument panel as that readout is calculated from the fuel injector pulses. (but obviously the real mpg will drop). apparently the heater uses around 0.5litres/hour on max and 0.3litres/hour on low.
Bigdave it looks like you flame/temp sensor is faulty if it reads 550c and therefore won't start.

[Chrispb]

What colour is this wire you say doesn't  go anywhere or if you can't  make out the colour what pin number on plug

[bigdave982]

Chris
Think it was red/black and the one above the thick brown (or maybe the thick red . It was on the heater side of the plug,definately didnt match up to car side,no terminal and the reverse (cable)side blanked out. Just assumed that the heater is fitted to a variety of vehicles and that wire nit used on galaxy

[barlidge]

Hi.  My Aux Heater runs constantly, regardless of engine temp, on c the outside temp. is below 13 degrees.

is this correct operation?  (I'm guessing not?)

If not, what should I be looking for as the fault please?

I'm sure I recall a similar question being posted a month or  two back.  Since then I've paid slighty more attention to mine and yes even after a 1.5 hr drive home - coming out of central London then 35 minutes solid A1 driving mine is still running.  I replaced the fan and ecu last year and its seemingly faultless since so I'm not worried.

If your concerned the best bet would be to hook up vag/vcds and log the live data regarding engine temp and aux heater in/out temps and post those up.

[bigdave982]

So ive stuck a new flame sensor in and still reading over 500Ã,°,
Any other ideas?

[insanitybeard]

Wiring short somewhere or ECU gone kaput? Is yours a D5W-Z model?

[bigdave982]

Vagcom says b/d5w

[insanitybeard]

It's the later D5Z-F ECU's that seem to give trouble normally, not the earlier ones like yours, however, a while back I recall barlidge replacing his on an earlier model heater, though for a different fault......

[bigdave982]

Ebay item number, anybody bought from these guys?
261654145721

[Chrispb]

Dave is the heater off the car, I have a temp and overheat sensor you can try.
I take it your still off as I haven't seen you.

[barlidge]

Ebay item number, anybody bought from these guys?
261654145721

No but I have bought these:
http://www.eberspacherparts.com/index.php?cPath=71_74

And:
http://www.ebay.co.uk/sch/olliparts24/m.html?_nkw=&_armrs=1&_from=&_ipg=25&_trksid=p3984.m1439.l2654

If the sensor is reading 550 degrees from cold and you've changed the sensor and checked connections then I would suspect ECU fault.  May be well worth taking Chrisb's offer of substitute sensors to confirm.

[bigdave982]

So i was wondering
Can yo scan a heater off the car for fault codes?
Wiring diagram has a diagnostic connection on multiplug so can we just connect vagcom to this?
Think i already know the answer ☺☺

[Chrispb]

er no

[Mirez]

Actually the answer is yes, I made a little test rig for them a while back when I was playing. Pin 7 is the K-Line so if you get yourself an OBD2 plug you can then make the relevant connections to test it on a bench using a 12V power supply

[Chrispb]

Stand corrected as always.

[bigdave982]

Actually the answer is yes, I made a little test rig for them a while back when I was playing. Pin 7 is the K-Line so if you get yourself an OBD2 plug you can then make the relevant connections to test it on a bench using a 12V power supply

Cheers marks, i suppose a lil wiring diagram etc would be too much to hope for??☺

[insanitybeard]

There's one in this reference library article...... (you'll need to download the PDF)

[bigdave982]

Ill check later wont open on my phone

[1958steveflying]

Actually the answer is yes, I made a little test rig for them a while back when I was playing. Pin 7 is the K-Line so if you get yourself an OBD2 plug you can then make the relevant connections to test it on a bench using a 12V power supply

Is this pin 7 wire the blue/white from the heater which is the Eberspacher diagnostic wire ?

[bigdave982]

Well im a bit worried
The heater i bought off greggers has been in about a week
Very little noise from it and no smoke,cant always hear the dosing pump either

Cant be right

[gregers]

is it warm/hot to touch??
i know when i had 1 on my gal i couldnt always hear it,but i still have the scars on my fingers when i checked it........

[bigdave982]

Oh yeah exhaust get hot vagcom reads ok  get up yo operatin temp in about 4 miles at ambient temp of 2Ã,°
Might chuck a glow plug in it but not for a while

[gregers]

im sure you have already looked at this but is your run on pump working?

[bigdave982]

Gregers,no probs i was beimg a bit tongue in cheek
Im happpy with it nice and toasty

[insanitybeard]

Maybe I'll get mine sorted in time for next winter! 

[gregers]

Gregers,no probs i was beimg a bit tongue in cheek
Im happpy with it nice and toasty

glad your happy and its working.

[stuiescenic]

Hello, i have been part of the forum since buying my Alhambra in June. I had problem with the heater (D5Z-F) not working and reading the faults showed short to ground faults.
I removed it and came to the conclusion that the heater probably hadn't worked for a long time so bit the bullet and got a brand new one from ebay germany (wwtrade24) and also repaired the aux water pump.
After fitting it worked straight away but like a few of you noticed it would keep running even if the temp gauge was at 90c. I looked at it with my VCDS to see what was happening.
What i found is that below roughly 10c the heater will fire up and run at full heat (combustion temp about 260-270c). The temperature gauge will then move to 90c even though the water temp is about 70c and rising, and only when the exit temp from the heater reaches 80c will it then go down to half power (combustion about 160-180c i think!).
From here the heater carries on until exit temp of 85c then it goes on cool down and switches off. I then put all my interior heaters back on to drop the temp and at 75c it then fires back up.
I suspect that my thermostat is opening slightly early as it very rarely drops to low power at present but that's a job for the summer, plus the heaters are always working hard!!

I hope this helps hope i have not missed anything out!

Stuart