I should have been clearer when I said I was referring to the car not the Webasto.

I seem to remember Chrysler's own diags refer to it, which surprised me because I would not expect it was on a Chrysler diagnostic. I have no experience of the Webasto but a lot of experience with the Erberspatcher and they are much the same thing. I would have expected to find all, and I mean all COMMS on the Webasto device itself, and not part of the cars logic.

 

Manual says this: Heater does not operate: Diagnosis cabin heater ECU using the DRB-III and the procedures listed in Vehicle Performance under Cabin Heater Diagnosis in Group
18.
And also:
NOTE: Failure to prime the Dosing Pump after draining the DCHA fuel line will prevent DCHA heater activation during the first attempt to start the heater. This will also set a Diagnostic Trouble Code (DCT) in the DCHA Control’s memory.

It seems to me the DCHA is connected to the cars CPU system but also has some digital brain or at least memory of itself..

 

Yeh - I've read that - I assumed that a Chrysler cabin heater is an AirTop, if it has a water supply its a UK / Euro water system called ThermoTop. The AirTop [air space heater], not the water variant called a Thermotop [Coolant water heaters]. Both Erberspatcher and Webasto have both. These things are fitted to most HGV's, British Gas, Telecomms etc and have ben in this country for 30 or more years. Thy originated in the yacting & boating world - you might get more insight by trawling the boating forums.

Hope this helps.

 

EUREKA!
The DCHA is working again!I was reading through all diagnostic advise in the manual and most ends with "replace the whole DCHA unit" but one of the very few solutions possible without a DRBIII scanning tool, special equipment or replacing the unit was resetting the unit by removing fuse #15 for 5 seconds with the engine running...

Since I assumed my DCHA was permanently locked out because the fuel line was disconnected for a very long time I already tried to reset by disconnecting the battery for 30 minutes but that only resulted in loosing all my radio channels but still no DCHA.

Now I started the (cold) engine with heater on "max" and noticed DCHA not working. I opened the hood and removed fuse #15 for 5-10seconds and replaced the fuse.
Voila! I could feel an airflow coming from the DCHA exhaust

 

Good for you for relentlessly chasing it down. REM it runs for a minute or so after you switch off , lock up, and walk away, this often-times freaks people out when in fact its normal. Congrats ............ and welcome to the benefits of the AUX heater, in your case your 'extra mile' of effort made it a cost free extra.

 

That's interesting, the aux heater on my 2007 GV 2.8CRD is under (more or less) the drivers seat. You can hear it running, if it is running when you turn the engine off. But also if you have a thermostat problem, it is quite common for it to stay open, the aux heater may not turn off because the engine coolant does not get warm enough (in winter) You can usually turn the heater off by reducing the cabin temperature you will see the amber warning on the dash when it is on. It simply provides heat on cold mornings because it takes a diesel a while to warm up...


Radiator cap can cause loss of fluid. And AC will leave a puddle if it is running and you did not notice


I would worry if the aux heater did not smoke when it shuts down (automatically) it is really just a little oil fire in a box that warms coolant.

 

is that a newer model light? On my 2002 there is no light on the dash indicating the Aux heater is running.
I can tell it runs by a faint whizzling sound and airstream from the Aux Exhaust but no light on the dash.

 

Its :

- 3 wavy arrows [orange coloured lit icon]pointing upwards with a single horizontal line under them
- on the extreme RHS of the information bar [not the EVIC (electronic information centre)]
- the information bar is the light grey eyebrow shaped grey bit in the pic below above the steering wheel



Your model may not even have an information bar !

 

I do got that info bar but there's no 3 wavy arrows
Not even when I check the lights at startup, in the "eyebrow" there's left and right blinkers, the oil-can and a red dot.

 

I disconnected the fuse for some 20 sec, but heater light didn't come up. I can hear the heater running and sometimes can feel the smoke, but unfortunately no arrows light on the panel.