Late Aux Heater D5z-f Model Pictures In Bits

[Ginettamad]

Well I have finally got my AUX heater apart and sadly had to snap or grind off several seized in screws to get the top covers off. Even the exhaust bracket was seized and snapped and as my car is only 5 years old with 40K on it I suspect most of you will have the same issues to contend with. The Glow Plug is apparently not such a problem on these units and its hard wired into the main socket. There seems to be very little info on how to test and repair these units but if anyone has TIS or VW parts and repair details to add that would be great. I have gleaned lots of info from Russia and the CZ where the heater must be used most of the year and Ebby dealers are not allowed to help car owners with OEM heaters due to the Ford VW licence agreements. Many other threads discuss the AUX heaters but few refer to this late Model presumably still used in Shrarans and Alhambra’s?

 

 

Here is the Model number label and the D5Z-F unit is quite different from the earlier models with the cable going into its top not base.

Temp sensor from under Wipers 10 degrees switch on.

This is what the plug pins look like connecting to the car.

This is the main parts showing fan unit, burner,and water jacket casting all cleaned.

This is the modern ceramic Glow Plug and the small round water temp sensor or overheat sensor not sure which but it sits in the water jacket? The wire insulation to this sensor has broken down exposing the copper so this could have caused a short which would stop the heater working???

Here is the sealed control unit which are claimed to be the main cause of problems with this D5Z-F heater and around £300 to replace (ridiculous in my view)! So far I have these detail from RU web site

Ebby part number 225205002001 The control unit 12B D5Z-F Hydronic II-F MPV VW (5HB 008 885-00)

 

Now are these repairable by stripping away the Silicone water proofing on the PCB????

 

These are pretty simple interesting machines but as a group we need to be able to access alternative parts for a reasonable prices otherwise we a stuck having to use main stealers who are often not great with Aux Heaters.

Harvey

Edited November 4, 2010 by Ginettamad

[Ginettamad]

Well I have tested and cleaned my D5Z-F heater sensors and flame mesh although it was stuck in its tube.

I have taken sensor resistance measurements but dont know what they all should be but after sourcing a S/H heater I have swapped its ecu onto my heater and put it all back together. Fingers crossed it will work but the S/H heater looked very corroded and used inside so I suspect that one hadn't run for some time either. At least I can send it back to the seller within 3 months if its ecu is no good either. I'll also test the other heaters sensors once thats in bits too.

I have also run wires from the outside temp sensor to the dash to fit a Off switch for the Aux Heater to save all the short stop starts stressing the glow plug.

 

Also something to think about is battery power could reduce the way the Aux heater works if the volts are lower than normal. They do sense under or over voltage to shut down and to get that plug hot enough they need a lot of power. Mine is getting low as its been on for 5 years now and the little window has gone clear suggesting replacement? Bet they are not cheap?

 

As its cold and dark after work I'll re-fit the heater at the weekend and see how it goes.

Will let you know what happens later.

H

[Mirez]

Batteries about

[chrispb123456]

Well I have tested and cleaned my D5Z-F heater sensors and flame mesh although it was stuck in its tube.

I have taken sensor resistance measurements but dont know what they all should be but after sourcing a S/H heater I have swapped its ecu onto my heater and put it all back together. Fingers crossed it will work but the S/H heater looked very corroded and used inside so I suspect that one hadn't run for some time either. At least I can send it back to the seller within 3 months if its ecu is no good either. I'll also test the other heaters sensors once thats in bits too.

I have also run wires from the outside temp sensor to the dash to fit a Off switch for the Aux Heater to save all the short stop starts stressing the glow plug.

 

Also something to think about is battery power could reduce the way the Aux heater works if the volts are lower than normal. They do sense under or over voltage to shut down and to get that plug hot enough they need a lot of power. Mine is getting low as its been on for 5 years now and the little window has gone clear suggesting replacement? Bet they are not cheap?

 

As its cold and dark after work I'll re-fit the heater at the weekend and see how it goes.

Will let you know what happens later.

H

Hi there

There's no reason to suspect the D5-ZF is that much different to the D5-WZ in respect of the upper and lower voltage cut off, iirc 10.something volts for the lower limit, that may safeguard the heater but you will be unable to start the car.

 

Good Luck for the weekend :)

 

Mark (Mirez) did you sort out that Vag-Com list for me?

 

cheers Chris

[Mirez]

10.2V to be exaxt and 16.4V for the upper, but I think the point is not that the thresholds changed between the two - its that if you have a battery on the way out then a low voltage condition could impede the start of the heater. However In reality, 10.4V would probably struggle to turn a cold diesel engine over anyway so I doubt you be that concerned at that point! :)

 

That said the most I've seen was a 1.2V loss between the battery and aux heater - its therefore conceivable that a battery at 11.4V could actually be at the threshold voltage of the heater although the loss is generally more like .4V

 

Chris, waiting for you email address buddy :)

Edited November 15, 2010 by Mirez

[sotal]

I don't think your old battery would play any part in any faults etc.

 

The Aux heater doesn't start until after the car has started up at which point your alternator is running and therefore the voltage will be higher. The only time voltages would play a part is if you had a duff alternator or if you fitted one of the timer kits to start the heater up without the engine running.

[George106]

Just to add, when I was "playing" with my D5WZ, heater shut down when battery voltage was around 10.9V and there wasn't enough juice for engine to start :) .

 

George

[Ginettamad]

Points taken re Battery and yes mine is getting touch and go to start the engine so looking for a new one soon!

The D5Z-F is however a completely different machine to the earlier models. Its actually got less parts but a much more complicated and expensive ECU or control unit. It also uses a ceramic Glow Plug which are supposed to never need replacing but people still change em. The burner design, water jacket, fan unit, and sensors are also different.

So I'm not sure what the cut off volts would be but on a cold dark frosty morning most would give the battery and alternator hell i.e. Heated Screens both on, lights on, demist on Mirrors etc all at the same time as the AUX heater is trying to heat its Glow Plug which on my bench took around 15 seconds to go red. The suggestions were only theory anyway as just looking for worst case scenarios???

Its too bl--dy cold here to be under my car anyway!

Luckily on my run to work I average 70MPH so the engine still warms up but when I come off the motorway the temp gauge goes back down to about 1/4 for town driving at 1 degree C.

Harvey

Edited November 16, 2010 by Ginettamad

[sotal]

I still think providing you have a healthy alternator even with all that stuff on you would still be above 12v all the time. If you are worried try it, just put a voltmeter across and start her up in the morning, and switch everything on headlights, heated windows etc, I'm guessing you will be above 13v so the aux heater will have no problem.

 

 

I recently read about someone fixing one of these by replacing the ECU bit which cost them

[niallsan]

Points taken re Battery and yes mine is getting touch and go to start the engine so looking for a new one soon!

The D5Z-F is however a completely different machine to the earlier models. Its actually got less parts but a much more complicated and expensive ECU or control unit. It also uses a ceramic Glow Plug which are supposed to never need replacing but people still change em. The burner design, water jacket, fan unit, and sensors are also different.

So I'm not sure what the cut off volts would be but on a cold dark frosty morning most would give the battery and alternator hell i.e. Heated Screens both on, lights on, demist on Mirrors etc all at the same time as the AUX heater is trying to heat its Glow Plug which on my bench took around 15 seconds to go red. The suggestions were only theory anyway as just looking for worst case scenarios???

Its too bl--dy cold here to be under my car anyway!

Luckily on my run to work I average 70MPH so the engine still warms up but when I come off the motorway the temp gauge goes back down to about 1/4 for town driving at 1 degree C.

Harvey

 

Really well done with those pics. I attempted to disassemble my heater earlier this year- its def the same as yours. When I discovered that you had to drain the water/coolant to get it apart I cancelled the whole operation. Mind you I did get a sneak peak through the top cover and discovered that the glow plug was a pre-wired deal. A few months later I borrowed my buddies VAGcom and got a dosing pump error(short circuit). Changed the dosing pump- (scrap dealer, and had to tell him where to look for it!) Still no joy.

Questions:- 1) Is the dosing pump wired into the control module in the heater? I'm only assuming it is.

2) any idea where you can buy the control module,

3) Is there much problem refilling the coolant system, with air-locks etc..?

 

Oh, by the way, I have a feeling the module was fried when the back-box of the exhaust was being welded!!!!!

 

N

Edited November 17, 2010 by niallsan

[Ginettamad]

Points taken re Battery and yes mine is getting touch and go to start the engine so looking for a new one soon!

The D5Z-F is however a completely different machine to the earlier models. Its actually got less parts but a much more complicated and expensive ECU or control unit. It also uses a ceramic Glow Plug which are supposed to never need replacing but people still change em. The burner design, water jacket, fan unit, and sensors are also different.

So I'm not sure what the cut off volts would be but on a cold dark frosty morning most would give the battery and alternator hell i.e. Heated Screens both on, lights on, demist on Mirrors etc all at the same time as the AUX heater is trying to heat its Glow Plug which on my bench took around 15 seconds to go red. The suggestions were only theory anyway as just looking for worst case scenarios???

Its too bl--dy cold here to be under my car anyway!

Luckily on my run to work I average 70MPH so the engine still warms up but when I come off the motorway the temp gauge goes back down to about 1/4 for town driving at 1 degree C.

Harvey

 

Really well done with those pics. I attempted to disassemble my heater earlier this year- its def the same as yours. When I discovered that you had to drain the water/coolant to get it apart I cancelled the whole operation. Mind you I did get a sneak peak through the top cover and discovered that the glow plug was a pre-wired deal. A few months later I borrowed my buddies VAGcom and got a dosing pump error(short circuit). Changed the dosing pump- (scrap dealer, and had to tell him where to look for it!) Still no joy.

Questions:- 1) Is the dosing pump wired into the control module in the heater? I'm only assuming it is.

2) any idea where you can buy the control module,

3) Is there much problem refilling the coolant system, with air-locks etc..?

 

Oh, by the way, I have a feeling the module was fried when the back-box of the exhaust was being welded!!!!!

 

N

See my other posts re the fault and yes the dosing pump was the error message but that is controlled by the

[davewill]

Harvey, please excuse me hi jacking your excellent posts and pictures.

 

As you may have seen i have posted this week, as my Aux Heater has stopped working (2006 Mkll 1.9TDI 115)

VAG com has thrown up error code 65535 Internal Control memory Module

 

My question is (and please excuse my ignorance, as i am no mechanic), Is the Internal Control Memory module part of the Aux Heater, and therefore shown in your photos, or, is it housed elsewhere in the engine bay??

 

If you could let me know i would appreciate it

 

many Thanks, Dave

[sotal]

Dave - I believe it is the bottom picture in the first post above

[Mirez]

Thats correct, the control module is bolted to the side of the heater and makes up the case. 65535 is an internal memory error, reset the code and see what happens. Generally on non critical kit (such as the heater) then if its still working then ignore it, else replace.

 

I see no reason why those with the later Z-F models couldn't swap them for the previous Z varients, the revisions seem to be largely internal.

[Dave-G]

Thats correct, the control module is bolted to the side of the heater and makes up the case. 65535 is an internal memory error, reset the code and see what happens. Generally on non critical kit (such as the heater) then if its still working then ignore it, else replace.

 

I see no reason why those with the later Z-F models couldn't swap them for the previous Z varients, the revisions seem to be largely internal.

 

I could be wrong but I think the later shalaxies had to become can bus complient - so that would require all ECU's to be connected through a common gateway......... or somink loike thaaat. :(

[Ginettamad]

Well I spent Saturday morning under the car again and in the process have gone down with bloody Man Flu??

I had to replace a hose I damaged then clamp off the hoses to remove the copper pipe bridge. I only lost about two cup fulls of red anti freeze which I caught in a bowl then filtered and returned.

Getting the rebuilt heater back on was quite tricky as fisrtly you need to remember which hose goes to which inlet (thanks to CZ web site pictures for that one)!

Once the hoses were on I then found it difficult to line up the hoses and fuel pipe in the correct angles when pushed up into place but after several attempts and lots of swearing and bloody knuckles it went back into position.

I used the original hose clamps and was worried they would leak but they seem ok so far as I guess they dont have much pressure behind them.

I wired up my Dash switch from the outdoor temp sensor then started up the car then switched the heater on and quickly jumped under the car.

The AUX Heater fan started up ok then some promising sparks shot out the exhaust then hey presto its was running again. I then said my prayers hoping it wouldn't leak and after two days running all seems ok.

On Vag-com it showed an initial overheat probably due to air in the water system but once the fault was cleared it showed the heater running up to 275 degrees and turning down to the slow speed once the water got to around 72 degrees.

So apart from the clean and service as I swapped the ecu from the scrap heater and that seems to have cured mine as I suspected the original VAG 1413 fault re the dosing pump was incorrect as the pump runs fine. It also does not click like the older pumps do for reference.

Now I wonder if I can return that scrap heater?

Snow forecast but I'm not worried now!

H

[Bigjeeze]

Thats correct, the control module is bolted to the side of the heater and makes up the case. 65535 is an internal memory error, reset the code and see what happens. Generally on non critical kit (such as the heater) then if its still working then ignore it, else replace.

 

I see no reason why those with the later Z-F models couldn't swap them for the previous Z varients, the revisions seem to be largely internal.

 

I could be wrong but I think the later shalaxies had to become can bus complient - so that would require all ECU's to be connected through a common gateway......... or somink loike thaaat. :18:

 

Long time no hear Dave - Welcome back from the ether!!

[Ginettamad]

ECU is not bolted to the side but sat under the top cover on top of the water jacket. Both top covers need removing to access it as the fan one fits under the ECU cover stopping that being removed on its own.

Yes it is canbuss readable and I doubt it would be compatable with the earlier cars easily. If a much more common earlier D5W heater would fit the later cars then that option may be possible although with some pratting about. Earlier cars have two sets of wiring leads going to them this has just one etc etc???

Fingers crossed mine is still working and it was frosty this morning!

H