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Is there any way to test the function of the cabin pre-heater. My car a 2005 2.7 Diesel. I remember some time ( a couple of years) ago smoke coming from the front nearside wheel arch when starting the car on a very cold morning I paid no heed to this having read that this happens and assumed the heater was functioning. Since that time I have never seen it again and the cabin does not heat up quickly, I assume it should when cold starting. I haven't bothered with it too much having bought an XF, however during these past winter months I've been aware of how quickly the cabin heats up in the XF when cold starting so I thought I'd look into it. I have all intact fuses, the next step given no other easy option is to remove the wheel arch lining and have a look.

You are unlikely to deduce much by looking at the heater unit. All the clever bits are inside or in the control module.

As with all things electronic, plug in diagnosis is the first point of action. Without that being done, everything else that follows goes into the guess work category.

I deal occasionally with these and other similar heater units on boats. If I have a customer complain about the heater, the first thing I do is get the local specialist in on the job. He has the diagnostic gear, the knowledge and the experience together with access to spare parts. Believe me when I say there will be several hundred reasons why a heater can fail to perform. Some causes are simple, other vastly more complicated, obscure and expensive to fix.

Unless you have the correct level of diagnostic gear and have previous hands on experience of this type of unit, I would leave well alone and take the car to a local independent dealer for diagnosis in the first instance.

Mike

Hello Mike
Thanks for the prompt reply, I won't waste my time at this point having a look then although curiosity is nagging me now.
I had Eberspacher heaters on two of my boats in the past, I assume this unit is the same, on start up they always emitted smoke so I had no occasion to fiddle with them.
I haven't missed the heater for a few years on the car so a few more is not going to make any difference until I can't resist the curiosity and have a bit of a fiddle.
Dave

These units, be they Eberspacher, Smiths Webasto, Mikuni etc all work on similar principals.

The thing that they all share is complex electronic circuitry, David. So without the appropriate test diagnosis gear, an owner/user is pretty much stuffed as far as their own maintenance possibilities are concerned.

Last year I encountered a very, very early Eberspacher unit on a boat. It was clear it had had a hard life, was badly installed and had been guzzling water sodden fuel. We replaced the cabin thermostat on the recommendation of the local agents. Even more coded signal lights then came on. We realised we were beaten so called the service guy in. During his basic diagnosis, he tried a couple of quick fixes but we ended up ripping the entire system out of the boat for him to take back to the workshop. Parts sourcing was problematical and it was three weeks before we saw the unit again. 80% of it was new! The unit was a bit like Triggers Brush!! The rebuild cost us around £360 from memory. It was money well spent because although we are experienced maintenance operators ourselves, we could never have got this unit back together having neither the relevant experience, tooling or access to the specialised parts network.

Some things are best left to the professionals and diesel heater units fall into that category.

Mike

As I recall the units can get locked out. This occurs when there have been several unsuccessful attempts to start it. For example, I think it won't operate if you have less than a 1/4 tank of fuel.
I seem to remember that there is a way of resetting it but I can't remember what it was or where I found it. One of the forums I think.
It will also only operate in cold temperatures (less than 5 degrees?).
Sorry to be vague but I do recall that I reset the one on my X350 and I didn't need a diagnostic tool to do it.
Hopefully that will give you some ideas - sorry my recollection is so patchy!
Regards
David

It would appear that I posted the details a couple of years ago on the X350 Forum in the Climate Control section and I'd forgotten! At least I can remember now how to do it!
Now, have I had my lunch yet and what did I come into this room for?

Hello David
Although I think the ambient temperature is too high now I'll find the fuse pull it and wait a while before putting it back in. Thanks for the tip. I don't suppose there's a way to fool the heater in thinking its freezing
David H

Hi rosemary. You will need to re set the burner or Fuel Fired Heater as some call it. I use my icarsoft i930 to do this. After many attempts to get mine to work on a regular basis I have found that if I operate the climate control manually the burner works fine every time. When I say operate manually what I do is start the engine with the climate control off, then turn climate control on. The burner should start and do it's job. Before you turn off the engine turn the climate control off. At this point the burner will go through it's shutting down cycle and it should work next time you need it.

Having read many post's on this subject on here and other forums I put it down to me only doing short journeys so the burner does not run it's full cycle, or the correct software was never installed into the climate control brain from the outset. The latter makes sense as it's only the diesel engined cars that have the burner, as diesel's are slower to heat op than petrol engines.
I hope this is of some help to you and others.

Jeff

Hello Jeff
Thanks for the tips I'll try it and see what happens.
Thanks
Dave