AUX Heater probs - even after swapping out! - Helllppppp

[Fraz-ktf]

Hi.

I had VAGCOM fault codes and my Aux Heater was not working.  The car took around 10 miles / 20 mins to get to temp, so I  fitted a known working Aux Heater from another vehicle but I'm now getting a different fault:

Control Module Part Number: 7M3 815 071  D
  Component and/or Version: HEIZG. B/D5W       0001
           Software Coding:
            Work Shop Code:
4 Faults Found:
01414 - Combustion-Air Blower (V6)
        36-00 - Open Circuit
01414 - Combustion-Air Blower (V6)
        36-00 - Open Circuit
01414 - Combustion-Air Blower (V6)
        36-00 - Open Circuit
01414 - Combustion-Air Blower (V6)
        36-00 - Open Circuit
What does this mean please?

I can clear the faults and they don't come back immediately but the following day, they are back!.

The Aux Heater I removed was a D5Z-F - that was reporting a "Short to ground" error (Which we deduced was down to it's own electrics)

Interestingly, the above fault codes were also apparent when it was working ok on the 115bhp Gal it came from.  I checked the plug, before fitting it all, so that's ok but is there any way of checking the operation of the unit, without waiting until it's 10 degrees outside?

Thanks

[Mirez]

Combustion air blower is the main fan on the unit and unfortunately it sounds like the motor is on the way out which causes intermittent 01414 codes. It'll still work on and off until its completely dead in much the same way as the run-on pump does when its brushes are failing.

[Fraz-ktf]

Combustion air blower is the main fan on the unit and unfortunately it sounds like the motor is on the way out which causes intermittent 01414 codes. It'll still work on and off until its completely dead in much the same way as the run-on pump does when its brushes are failing.

Thanks.

Is the fan swappable? or is it a whole new unit?

Or better still, can the motor be "Serviced" by my retired engineer-wizard?

[Mirez]

Yeah it breaks apart from the heater so can be replaced individually. I've not tried to service the motor but its likely to be strippable/accessible once removed so a wizard might well be able to replace the brushes

[Fraz-ktf]

I/we stripped the heater down, prior to fitting and copper greased the bolts, cleaned it all out and tested the plug, just for future-proofing any removal issues, so it should be fairly easy to strip.

Do you know if this can be done in-situ or have I got to drain the coolant system on my head again? 

. . . We're off to see the Wizard . . . . .

[SilverBeast]

Unfortunately you will have to remove it again as you need to:-
(i) Remove the hoses, waterand diesel, inlet and exhaust pipes.
(ii) Remove the plastic cover over the contoller PCB (which is why you need to remove the hoses)
(iii) Remove the plastic cover over the fan (which also has a piece from above over it)
(iv) You can then take out the long screws which hold the fan motor cover and the combustion chamber together.
NOTE:- You can probably remove the motor/blower (or at least check the wiring as that may be all that's required) without spiltting the combustion chamber off as it was hard to seperate on mine and you may damage the gaskets, which I couldn't find replacements for, though the main round one is the same as the older D5W-Z

[attach=1]

[SilverBeast]

Forgot to say. On mine most of the screws had to be drilled out, including those holding the plastic covers in place.  I then had fit helicoil inserts to them in order to fit screws again.  The only ones I didn't have to do this with were the long ones you need to remove in order to get the fan cover off.

[marinabrid]

You don't have to drain the system to get it out,  all you need is 2 pipe clamps    draper make them, just clip one over each water pipe near the heater and the only coolant loss is the bit thats inside the heater.

[SilverBeast]

Clamps like the blue ones in this picture (brake hose clamps).

[attach=1]

The grey things are rubbery blanking grommets from an electrical junction box, that were just right for capping the hoses or aluminium pipes.  If you need to keep the heater off for a while and still use car the remove the shorter coolant hose and the longer hose will loop round and complete the cooling circuit.  I ran mine for weeks like this.