Eberspacher heater system - haer fan relay?

With my "new" 855 TDI 1996 came also an Eberspächer Hydronic(?) preheating
system, which burns fuel to heat up coolant and passenger room, starts ok with
remote control TP 48, is about 8 years old, I presume. The coolant is being
heated perfectly, the heater fan for the passenger room does not start though. I
think there is an extra heater fan relay built in with the preheating system.
Where should I search for it, what does it look like? Fuses are ok. Heater fan
works ok with genuine heating system of the car.
Thanks for any input.
Viktor

 

Hi Viktor,
Does your car have A/C or ECC?
My 855 TDI has a never Hydronic and there is one external relay on the
cable tree.

Cheers Per

 

Hi Per,
thank you for your input.
you asked

I think it is ECC, if it means a heating/cooling automat, where you set only the
temperature and the system decides how to achieve it. Fan automatically
adjusted, directions of air flow automatically etc.

I have had (and actually still will keep it as a summer car) a 1989 745 TD,
where there is plenty of room under the bonnet. Now looking into the new car,
there seems to be no space left for insertion of hands and fingers . Where
is the cable tree you mean? Going from the battery into the depths ...?

Regards

Viktor

 

The cable tree goes from the heater unit to the battery via a relay and a
fuse box and to the timer inside
the car - if you have such installed. Further - on my car only one cable is
connected to the ECC control unit,
the one above the radio, where you adjust the temperature etc. There are 3
plugs and in one of these plugs
a cable from the heater is connected. This cable control the fan in the
car!!

 

There is a timer, set to 60 min heating period. If the car is not started within
this time, the preheating system shuts itself down, I read on the little leaflet
which came with the remote control. I also can hear a timer tick after starting
the heater by remote control. The fuse box of the heater with three fuses is
right besides the battery under the hood. Maybe only one of the fuses is for the
Eberspächer heating system. I was at a repair shop to have them have a look on
my system to know whether it really should be able to heat the passenger room.
The mechanic checked the first of these 3 fuses and said that it is ok. I myself
checked the other two, they are also ok.

So the relay should be under the hood and not inside the passenger room, if I
understand correctly.

I have also asked at a German language Volvo website www.alter-schwede.de about
this problem. Somebody answered that at his car the passenger room fan starts
only when the middle air distribution control knob is set to blow to the screen.
That was a "dirty hands free" try, unfortunately it did not work. At which
position do you keep the air distribution knob when you want the passenger room
preheated? And the other knobs? Unfortunately I do not (yet) have a manual for
the Eberspächer heating system but will try find one.

I tried to find out, what is where and have located a suspect for the relay,
which might be the one:
http://weisshaeupl.gmxhome.de/images/Auto/Volvoheizung1vga.jpg ?? The text on it
is Siemens V23134-A1-X65 12V R 61-15. The Hydronic heating unit seems to be
under the battery?

Is that the heater relay?

Then I had another idea. Could it be that the passenger room heating fan is
started only at temperatures below zero or near zero? Since at the moment we
have only a "calendar"-winter, and not a climatic winter, the heater might not
see any reason to start heating.

Regards
Viktor

 

I have the installation manual for the Volvo 850 TDI and I will check the
wiring when I find it.
The fan starts to run when engine temp. is higher than 30 - 40 celcius, this
is controlled by the
heater and has nothing to do with the buttoms position on the ECC unit.

 

I get varying info on that stuff. I contacted the previous owner. The heater has
been installed by a non-Volvo electric shop later. The previous owner kept the
recirculation switch always on and turned the fan on 1/3 manual speed. One guy
told me, his 855 preheater starts only when the middle knob is turned to the
screen...

If you could send me the wiring, that would be terrific.

Regards

 

In order to help you better could you find out what number and year your
heater has? Mine is a
Hydronic D 5 WS - with external waterpump and external control relay.
Did not find the wiring but I checked how I connected mine as I bought mine
on Ebay in Germany
and installed it my self using the Eberspächer installation manual for Volvo
850 TDI.

be out of order. Is the electrical
water pump running when the heater is running?

The cable (on mine - the color schwartz/violet) from the external relay pin
30 that controls the fan has voltage supply
via a 5A or 25 A fuse on relay pin 87. This fuse is located as one of the 3
fuses in the Ebersbächer fuse box.
The sw/vi cable from the relay pin 30 is connected to the A2 plug on ECC
unit, in this plug it is connected to pin no. 2.
When connected this way the fan start to run as soon as the engine
temperature is around 30 - 40 celcius, the knops on the
ECC unit has nothing to do with this fan control.

 

Hi,

don´t worry about the cabling any more:
I was surprised I received the installation instructions as PDF-file from
Eberspächer today
for what is probably in my car. The relay I suspected originally really IS the
relay for the heater fan. Now it should be possible to sort out in which part of
the system the fault is. I also now realized the little digital clock inside,
which I believed to be just a normal l little clock. It is the manual timing
system clock. It was not operating, probably after having removed the battery
from the vehicle.

So I will check next whether the primary circuit relay connections 85 (ground)
and 86 (+ through some kind of thermosensitive resistor). That should be dead or
low voltage when
coolant is cold and get alive enough to operate the relay solenoid when coolant
reaches about 30 degrees centigrade.

Regards
Viktor

 

Now that I knew how the relay is working, I took it out and checked its function
on the workbench. It works fine, unfortunately. Changing the relay would have
been the easiest job.

Should not bypassing the relay and applying 12 V+ on connector 30 of the relay
seat also make the fan move? Or is there some other fan regulating temperature
dependent system still working? This morning I had the timer set to start 45 min
before I left, the fan set to maximum, the rest on auto, the temps on max. The
engine coolant thermometer showed a temp about one third up the scale when I
turned the key. So the engine coolant was heated ok. When I started and drove,
the ECC did not start the heater fan until the coolant temperature had still
risen more. I will try to find in the VADIS how that should work.

Regards

Viktor

 

Now you can check the relay trigger cable from the heater - it should apply
12V
on the raly trigger when temperature is on rigth level - if not the trigger
source
in the heater does not work.

You can also check the fan circuit but applying 12V to the relay trigger -
this should
start the fan.

Remember not to have the key in the ignition unit.

Good luck!

Per

 

I have done these checks myself today with a completely cold vehicle after work.
I get 12 V on the line after some heating.

I did not do that. This bring to my mind - one reason why the relay might not
work when being in place could be bad ground contact. I will check that.

What I also did - I bridged the relay secondary circuit, that means 30 and 87,
that should give 12 V to the line to the ECC unit and start the fan. It did not.
I will next try to find out where the connector A2 (which should transmit the
impulse to start the fan) on the ECC unit is - if somehow easily accessible I
will check whether it is in place and whether any voltage arrived there. I am
not yet ready to give up and go to the shop. Who knows whether we will have
temperatures below zero this year any more...

The Vadis says in its section on the Ardic inbuilt parking heater: The control
unit is fitted with a connection (A:2) for connecting a digital parking heater.
When the heater is switchen on, the ECC control unit receives a signal from the
timer and the following outlets occur when the ignition is switched off:
The fan starts and is supplied with a voltage of 4,6 V.
With the air distribution control in the aut setting, air distribution is the
same as in the floor/defroster setting.
Recirculation is activated so that 90% of the air is taken from the passenger
compartment
Both temperature control dampers are set for max. heating.

I comprehend that the fan should start regardless of the settings of the
controls on the ECC-unit. I do not understand what they mean with "digital"
parking heater. It seems to be just enought voltage or not on the line to the
ECC unit, no bus line.

Thanks, I start thinking I need it...

Regards,

Viktor

 

Digitally could mean on/off. It seems that the Ardic heater is connected
the same way as mine; plug A2 - pin2 in the ECC unit. There should be 12V
on this pin from the trigger in heater via the relay and when this happens
you
will see the diodes for recirc (when on) and aircon go red and the fan
starts to blow.

 

I will put 12 V directly from the battery to this line and see what happens.
Should the fan start regardless of outside temperature? I

I have had a look at the UK-website of Eberspächer. They offer much more than
the Austrian website, which I have used up to know. They have at
http://www.eberspacher.com/files/pdfs/water_pdf/hydronicD4+D5wsc_technical.pdf
a detailed documentation for installation, not available at the German and
Austrian website. Very informative. There is also on page 19 the unit (2.15.9) -
an outside temperature sensor. I could not find out, how the outside temperature
influences the function of the heater. The factory installed parking heaters
(Ardic?) heat up for a shorter time when the outside temperature is well above
zero. Maybe the Eberspächer heater outside temperature sensor causes the same?
Maybe I will have to wait until next "winter" to find out.

Viktor

 

My guess is that there is no outside temp sensor - normally extra in
connection with
heater controlled fan function oly in the hot summerdays.

The fan should start regardless of outside temp.

Cheers Per