Auxiliary interior heater - How does it work?

[tobyd@callnetuk]

Hi there,

I have a left hand drive ex-germany car that is fitted with the auxiliary heater that has the timer control window just forward of the gear stick. I have no idea how it works or whether it works!

I am trying to find some instructions and also details of where the fuse is so I can get it working now the cold weather is here.

If anyone can tell me how it works and how to trouble shoot it (no life from the display) I would be grateful.

Cheers

Tobyd

 

[guydewdney]

a little more info on the car might be handy.

did you know that this was an option on the 'grand' 600 from the fifties? (however, that option had the timer in the glove box..)

It works by pumping petrol into a small firebox (rather like a domestic cenral heating boiler).

first things first, check all the fuses. theres usually some in the boot and some under the bonnet... but without knowing the car (the first three numbers of the chassis number will tell us what it is WDB 210? WDB 140? etc) its very difficult to be specific.

Mercs are usually quite logical in the operation of such things....

 

[tobyd@callnetuk]

My car is a W124 500E made in 1992.
I hope that this helps as even the MB mechanics looked at me blankly!!

Thanks.

 

[guydewdney]

i thought so from the threads you have responded to - however i had a look at my EPC and there is no mention whatsoever of an aux heater for the 124 500... is it a merc thing? or is it an aftermarket thing?


hmmm - actually - cant find it on any car on the epc... weird.

 

[tobyd@callnetuk]

I have seen it on foreign W124's before and it is briefly mentioned in the handbook for my 230TE but only has a quick description of how the buttons work. I'm wanting to know how the system works and how I might be able to troubleshoot it.

 

[tobyd@callnetuk]

I foundthis reference to the heater on an obscure web page -


'The auxiliary heater (Zusatzheizung, code 228) is a separate heating
system that works independently of the engine. It consists of a
separate burner unit, an electric water pump, a control unit and it
is connected to the coolant circulation of the engine. It is run on
the fuel of the car (either diesel or petrol, these are different
units for obvious reasons) with a separate fuel line from the tank.
This makes it independent from an electrical outlet and from the
engine. It is started either manually, with a timer (mounted on the
center console or in the glovebox) or via a powerful FM-wireless
remote (the Mercedes units for from about 500 to 1000 metres
depending on local circumstances. The latest versions are available
with mobile phone remote control as well.

Once it is started, a spark plug ignites the burner which heats the
coolant up and the water pump recirculates the water through the
engine. The system heats the coolant up to 80°C and works until that
temperature is held in circulation. Once the temperature of 55°C is
achieved, a separate relay starts the heater blower and this heats up
the interior.

Even at very low temperatures in Alpine or Siberian regions, this
heats up the engine and the interior within 20-30 minutes. Apart from
a warm seat when you step in, the heat melts all snow and ice on the
windows without further ado.

Very comfortable and a must in Southern Germany, Switzerland and
Austria.

Many German Taxis have it as well since it helps them keep warm in
Winter when the wait and have no engine running.'

I still need some info to get mine working as well as instructions so if this rings a bell with anyone I'd love to know.
Thanks

Toby.

 

[tobyd@callnetuk]

This is what the heater control looks like in the cabin.

 

[forrestdale]

I have an auxiliary pre-heater fitted to a 1991 Discovery. It's a Webasto unit, and the control is broadly similar to your one.

Although it's different from yours, the principle is likely to be the same, and you might want to do a Google search for "Webasto" in conjuction with other search terms like "troubleshooting" etc to get a general idea of how it works.

The following PDF documents were found amongst the first few hits of such a search, and give wiring and trouble-shooting diagrams:

http://www.techwebasto.com/automotive.asp
http://www.techwebasto.com/heater_main/heater_technical_bulletins/TSB_T_Top_Troubleshooting_Tree.pdf
http://www.techwebasto.com/heater_main/technical_publications_germany/Workshop/63378A.pdf


Forrest

 

[tobyd@callnetuk]

I have had contact from webasto who supplied the heater to MB and have subsequently obtained some pdf's of the operating instructions as well as a full manual for servicing and troubleshooting. The model no. is bbw46

I hope this will enable me to get my heater working and contact me if you wish me to email the pdf's to you.

Thanks

 

[Shude]

Webasto are the daddy when it comes to aux heaters and sunroofs! I spoke to a bloke at the Webasto stand at the motorshow and he said they make oem sunroofs and heater systems for practically every production car on the road.

 

[RichardM]

Sounds like a nice system to have, having the car warm and defrosted on winter mornings.