This what it looks like on mine, if that helps

 

Thanks Tim, however, those photos have turned out a bit small to see the detail.

This is where I am at the moment:

I've tapped into the wire coming from pin 3, however, when I ground it the the ignition on and off) nothing happens.

The is a whirling noise that comes from beside the battery when I turn the ignition on, though I think this is more related to the diesel supply to the engine than the heater.

Am I on the right track? Or are there any other things I can try to bring the heater to life?

Surly there must be a wiring diagram for these cars somewhere.......

 

Iv'e wired mine from pin 3 and have the same problem, the pump by the rear wheel arch seems to have gone on mine so I have just bought a new one from ebay. I'll let you know how I get on when it arrives. Does anyone know if when you activate the heater from pin 3, the power is also sent to the pump at the back ?

Scotty1

 

Hi, if pin 3 is connected to negative (I used the battery) with the ignition off, the heater should fire up. Mine did. I am currently working on an easy and cheap way of running a switch to it.
Andy

 

I have run a switch to mine and when I switch it on the webasto fan starts running but it doesent get hot like it should.

I have checked the rear heater pump but its not working so the heater is being starved of diesel. A new pump ordered from ebay should fix the problem.

Scotty1

 

So does the heater require the main diesel fuel pump to be activated in order to work? I always though that it had it's own pump built in to pull fuel from the tank seperatly from the engine.

 

pin 3 shouldn't normally have anything in it?!
the wiring on greddymops seems a different way from the normal diagrams...
Keith mentioned the tech webasto site for info, and I posted 4 links in the same new thread to the relevant bits everyone needs, about 3-4 days ago

 

It does have its own pump mounted near the off side rear arch. Mine seems to have gone so waiting for the new one to be delivered.

Scotty1

 

http://forums.mg-rover.org/showthread.php?t=157300

see the two variants of heater wiring in the the first hungarian site doc, which someone needs to translate from german... photos on page 3/10

 

I mention this again.. look at the two variants of wiring in the hungarian sites rover 75-specific installation! This might explain differences. As Keith says, something is awry with G's wiring and the big circuit dia loaded here only typifies one installation. Thats what they WOULD fit, but as we're finding whats on the diagram aint necessarily there!

One question for Keith/anyone.. is the 1530 Webasto timer output 'positive' or 'negative'? Trying to make sure i get my relay round right way...
Someone else said make sure you use a back EMF supression diode to ensure no damage by the relay to the timer..any thoughts anyone?

 

There is a bit of confusion about the wiring of the FBH/Parking Heater.

The FBH operates by a 12v feed from the ECU (when the alternator is running) via thermostat to pin 1 on the heater plug on a Slate/Grey cable.

The Parking Heater option operates by an earth feed from the relays via the remote control or timer to pin 3 on the heater plug on a Blue cable.

Pin 3 and the Blue cable are only present if the parking heater option is fitted, they are not there if only the FBH is fitted.

To add the parking heater option to the FBH you can either connect a 12v feed to the Slate/Green cable, or add a terminal to the plug at position 3 and connect that to earth.

 

OK then, I've seen it a couple of times now. FBH??? What's that?

 

 

Pondweed, thanks for the links to the above - top banana!

However, pins 3 and 6 are both connected. Six goes to the dosing pump, which is fair enough. Pin 3 however connects to line '61' - though what tis is I don't know (common ground, common 12v?????)

What about pin 5? The German drawing standards for electronics seem slightly different from any BS or EN standard I know.

So much for the simple one cable, 10minute job........

 

So when you say 'FBH' and 'Parking Heater', do you mean two seperate items? Or are those both terms for the same thing?

Just not sure what you mean when you say:

"Pin 3 and the Blue cable are only present if the parking heater option is fitted, they are not there if only the FBH is fitted.

To add the parking heater option to the FBH you can either connect a 12v feed to the Slate/Green cable, or add a terminal to the plug at position 3 and connect that to earth."

And considering my cable colours are grey and brown instead of blue and black, not really sure what the hell is going on!!!

 

So when you say 'FBH' and 'Parking Heater', do you mean two seperate items? Or are those both terms for the same thing?

Just not sure what you mean when you say:

"Pin 3 and the Blue cable are only present if the parking heater option is fitted, they are not there if only the FBH is fitted.

To add the parking heater option to the FBH you can either connect a 12v feed to the Slate/Green cable, or add a terminal to the plug at position 3 and connect that to earth."

And considering my cable colours are grey and brown instead of blue and black, not really sure what the hell is going on!!!

The Fuel burning heater is the heater itself and only runs when the engine is running and it is below 5 degrees. The parking heater option is an "add on" which switches on the heater at any time by remote control or a timer in the cubby box, and also operates the air conditioning. Not many UK spec. cars had the parking heater option as standard

 

Heater Cicuit Diagram.

All German Diagrams are done to the same standard and like most things in life once the code is cracked it becomes easy.
DIN = Deucher Industrial Notation They have a great thing going for them in as much as if it works well dont alter it. The same circuits and ideas are carried through by all manufactures. It seems to me that the only things that are standard in this country are lamp bulbs and bearings.

 

Hi Greddymop, I had the same question when new to all of this.

By the battery is a coolant heating unit that is powered by diesel and a small combustion chamber. This is a "fuel burning heater (FBH)" because it is a heater that uses fuel.

When the outside temp is below 5 degrees the FBH turns on. To test it works you can supply 12V to pin 1 (I've only just learnt this), or ground out pin 3


Now, wouldn't it be great if this system worked when the car was parked so that you can have all this happen before you leave the house? i.e. a Parking Heater. It is exactly the same FBH, but has add-ons such as timers that use pin 3 of the FBH. In this case, they ground out pin 3 to activate it.

Hope this helps.

 

Various modes of heater

I am not an expert on these auto models but from the diagram pin 5 feeds thro a switch and could be used for an Autunm setting. Throttles fuel to say 50% output , this stops the heater recycling and saves the glowpin from over use. They have a limited life and are the most disposable item in the system .
Looking at the diagram the are two configurations for the heater,
a) heater turns on and and heats up the circulating water in the main power unit (the engine)
b) there is a facility to connect the Climate control fan to run when the water circulating through the internal car heater is upto temperature.
The first opion assists in making it easy for the engine to start, warm oil and combustion spaces. The second warms the interior of the car for the driver.
There is usually a set time for this as the battery is being used. These heaters are voltage sensitive and it is recommended that the Battery voltage is always kept a high level. After the heater runs up at about 3 mins after starting the unit is taking full load from the battery and if the battery is not in ggod condition the heater will fail safe. On a fully charged battery most of these machines will run for 73 minutes and then shut down for a purge and start again. By this time the car should be up and running and the heater shut down. The fuel pump being exposed as it is should be wrapped in a product such a Sylglass. This is a mucky process but will protect the unit from corrosion and easy to remove for maintenance. DENSOTAPE can also be used. I hope that this has been of assistance to those who are cold.
Failing this then a warm coat and gloves, a hat also helps to keep you warm.

 

I usually deal with large (upto roughly 25MW) industrial burner equipment for industrial boilers for my job, and seeing the similarities between what I sell and this little 5kW unit are rather surprising - espicially the need for pre/post purging with the fan and the various turndown operations.

Anyhow, will try connecting a possitive 12v to pin 1 (which currently has no connection) and ground to pin 3 tomorrow and see what happens.

The only bugger now is that the bonnet refuses to shut properly!

Looking at the above drawing though, does anyone know what the four lines (15, 30, 61 and 31) connect to? I'm asuming 30 is the fused 12v possitive and 31 ground, but 15 and 61 are a bit of a mystery.

 

I usually deal with large (upto roughly 25MW) industrial burner equipment for industrial boilers for my job, and seeing the similarities between what I sell and this little 5kW unit are rather surprising - espicially the need for pre/post purging with the fan and the various turndown operations.

Anyhow, will try connecting a possitive 12v to pin 1 (which currently has no connection) and ground to pin 3 tomorrow and see what happens.

The only bugger now is that the bonnet refuses to shut properly!

Looking at the above drawing though, does anyone know what the four lines (15, 30, 61 and 31) connect to? I'm asuming 30 is the fused 12v possitive and 31 ground, but 15 and 61 are a bit of a mystery.

You only need to connect 12v to the Slate/Green cable or Earth pin 3, not both.

 

Greddy yours is wired up in a rather odd way has it been added later?

You are missing the K bus diagnostic connection for starters

I would not connect anything to pin 1 leave that for the Alternator via temp switch connection.

grounding pin 3 is all that is necessary to make it fire up
The fbh then powers up the solenoid pump itself so can control when it is on and off

 

Keith, that's what I was thinking, but grounding pin 3 gives no immediate response. Does it kick in straight away? Or is there a time delay before the combustion fan turns on and engages the FBH?

Raykay, I'd like to connect the grey/green wire to the positive supply, but it's connected to pin 3 - so don't want to fry the unit.

Either way, there's definitely something not quite right with my cabling.......would explain why it's never worked!

On another thought, have people cut the cable to pin3, or just tapped into it (Like I have in the photo)? Shouldn't make a difference, but I'm willing to try anything......

 

Yours is all wrong you need to find out where all your wires go

Pin 3 is normally empty unless a timer or Telestart has been fitted
I will tell you what should go where tomorrow just off to bed now

It is going to be a busy day tomorrow

 

Thanks Keith. Think I'll be getting the multimeter out tomorrow and doing a bit of investigation.

As long as the basic, minimum wiring connections can be achieved, then I can make a control system myself to control the thing. As long as it still works!

And bed sounds good - shame it's my turn to stay home with the fire extinguishers (I live in a thatched cottage - not ideal for fireworks night and inconsiderate neighbours!)

Until tomorrow me thinks.........

 

Just to throw a spanner in the works..........................


The circuit diagram I have shows the Slate/Green cable going to pin 1
The connector layout (925) in the electrical manual shows it going to pin 3 and does not show the K-bus connection.

(If it's any help, I tapped into the Slate/Green cable - with a relay to prevent 12v being fed back to the ECU - works OK.)

 

It does look like pin 1 must play an important role - the diagram on my previous post show that it is connected to the output of the timer gizmo - and the output must be a positive voltage (due to the internal wiring of the timer).

Pin 3 if triggered by an 'outside temperature' thermostat - which is obviously bypassed by connecting directly to earth.

Pin 6 connects to the pump - so is required.

Pin 5 connects to the 'summer/winter' switch - whatever that is! thermostat??

Pin 4 triggers the 'vehicle air fan' relay - though I'm not quite sure which fan this is. Can't imagine it being the main engine fan.

Pin 2 - is then left for 'diagnosis', and how that works is anyone's guess.

So as a minimum, I'd expect pins 6, 5, 1 and 3 to be connected up in order to operate properly, but in the real world, things seldom work out how logic dictates.........

 

Sorry been very busy or our new club site today so I forgot to post this here the way a correctly wired one is wired is as follows

2 pin plug -
pin 1 = +12v
Pin 2 = ground

6 pin plug -
Pin 1 input Slate/Green from alternator via ambient air temp switch
Pin 2 Red/Yellow/White input/output K-Bus
Pin 3 not used unless Timer or Telestart is connected then it is grounded to fire up the FBH
Pin 4 not used unless Timer or Telestart is connected then it provides 12V out to turn on Relay for ATC panel
Pin 5 not used
Pin 6 Brown/Pink output from FBH to Solenoid fuel pump

I won't post anymore on this subject here as I already now have a thread elsewhere

 

Heres whats under the bonnet of my 2001 cdt if it helps anyone.

http://www.easyrider01.btinternet.co.uk/rover75/webasto.jpg

Scotty1

 

That looks correct plus your wire you have added to pin 3!

Jon I forgot to say output of the timer is +12v it can switch a standard halfords type relay with no problem