Mine only fires us when it’s cold outside ( remote flash’s green every few secs )

Darren

There's a good description on this in the 2010-12 WM in the Wiki. Should give you a good idea of the workings  Cheers
Richard

(there are no such things as an ordinary FullFat, an ordinary cat or too many tools)
2011 TDV8 Vogue Santorini Black
Gap IIDBT

We have had various FBH faults over the years, here’s some symptoms and fix’s that worked for us:

1st fault:

Wouldn’t fire at all, SDD showed low battery voltage, a few weeks later the alternator died so I guess it wasn’t being charged properly.

2nd fault:

FBH ran but warm at best air produced, turned out to be a sticking change over valve meaning the FBH was trying to heat the engine up as well and struggling.

3rd and 4th fault:

Heater fires up and shuts down after a minute or so if you touch the outlet pipe under the bonnet it’s boiling hot, but the two heater matrix pipes above are stone cold. In our case this was a failed webasto pump, without circulation it was heating the water sat in the pipe to temperature and shutting down, it does this fairly quickly.

With a failed pump, the webasto will run fine with the engine running as the main coolant pump takes care of the circulation just check the exhaust.

In summary we have had a change over valve and two pumps in 5 years.

Otherwise it runs for 30 minutes and produces a loverly warm car! It defrosts the car in the morning in minutes.

Well the time came to finally test mine this morning at 6am and -1 degrees whilst on a night shift and ....nothing!

Approached the car in the car park and was all frosted over. Pressed the on button on my remote and the led flashes green. I could hear a blower/fan noise in the bonnet vent but nothing else. No smoke from wheel arch, no jet engine noise- nothing. Anyway I left it for a while and thought maybe it’ll take time as it is a 20 to 30 min cycle anyway.

Came back to the car after 20 mins and all I could see were two small holes in the frost at the bottom of the windscreen. Got into the car and it was freezing. Doors were stuck as well. Oh how I remember the TD6 doing this last year!

So something is activating but it doesn’t look like heat.

So that was a long wait for nothing! 2010 MY Vogue SE TDV8 3.6 Stornoway Grey- fully loaded

I’ve learnt most times it’s because the battery voltage is too low for the module. Regards

Daz

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2011 (61plate) 4.4 tdv8
sumatra black

previous cars

e46 m3
e53 x5

I’m just checking it with IID now

Tried the test function and it’s showing this

Click image to enlarge

I found the neat way to rule out the webasto itself is to see if it comes on with a cold engine?

Not sure about your model and year. But in my 2011 tdv8 the heater comes on with a cold engine to warm it up faster. Regards

Daz

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2011 (61plate) 4.4 tdv8
sumatra black

previous cars

e46 m3
e53 x5

This is exactly how I test it, if it comes on with a cold engine (hold you hand against the exhaust).. then the webasto is fine. Next I check the webasto pump, you can do that by firing it up from cold and touching the pipe work, it will get super hot for about 30cm but no further as you don’t have water circulation.

Battery wise when the engine is off the low voltage limit is 11.4 V for more than 10 seconds; the system is re-enabled if battery voltage increases to 12.2 V.

So yours comes on regardless of whether it’s activated then? 2010 MY Vogue SE TDV8 3.6 Stornoway Grey- fully loaded

Yes buddy.

When I start the car the fires fuel burning heater comes on to aid the tdv8 warm up. Apparently it doesn’t produce heat very quickly this engine. So to reduce wear it always comes on.

That’s how I knew it worked when my remote heating wasn’t working properly. But it seems that unless the battery is charged fairly high the module either doesn’t turn it on or cuts out after a short period.

I tested it last night and went for a 18 miles drive and this morning it worked for the full 20 mins. Regards

Daz

-------------------------
2011 (61plate) 4.4 tdv8
sumatra black

previous cars

e46 m3
e53 x5