Honestly, I've scoured the many posts and I haven't seen this one mentioned before.....

I've had my MY05 facelift TD6 since last August, love it. FBH has never worked. Colder weather and hundreds of posts about the FBH made me start investigating.....

Quite simply, it doesn't do anything, and it doesn't respond to anything. No fans, no pumps, no noise, no activity of any sort.

If I press the manual start button, then the only response is a flashing light at the top left hand side of the screen.

The evidence so far:-
1. The unit looks in very good condition - without dismantling, no sign of use, no dirt in exhaust etc.
2.Battery was new in December last, always at least 12.4v or above statically, 13.8v engine running.
3. Fuse 59 checked ok
4. Fuse 59 pulled to try a reset, no difference
5. Ambient temp sensor checked ok
6. When it last had MOT & service, my Indy checked and said no FBH fault codes. They also reported that they activated the pumps and fans and all seemed to respond - they heard them all operate.
7. Suspecting PCB fault, it I removed and sent it to French Mike. He found a fault - repaired a resistor, and on reinstallation.......no difference (but at least I know the PCB is ok now.....)
8. Disconnected the two vehicle plugs, re-installed battery. Found these voltages:-
- The 2 pin plug - 12.6 volts (correct)
- The 6 pin plug, between pins 1 and 2 = 10.6 volts stable (unknown)
- The 6 pin plug, between pins 1 and 6 = 0.1v stable (unknown)
9. Even stranger, all those voltages are there permanently - whatever position the key is in - including removed from the ignition. They do not change when you press the manual start.

My conclusion is therefore that the FBH is not receiving the "ON" signal.....

Thoughts and bright ideas more than welcome

Otherwise i'll have to either buy an IID or take it back to my Indy for more diagnosis......

Surely I can't be the first to see this

Cheers, Jon.

so it doesn't work on either timed climate or remote?

Can you get someone with a diagnostic such as auto logic to force it to run and ignite? if so there is nothing wrong with the unit and you are correct in assuming a control issue. Possibly a fault in the t90/91 receiver in the boot, which picks up the signal from the remote. Though if its not running on timed either then this is not likely.

It may be worth getting the diagnostics to reinstall the software for the FBH, possibly by removing it from the CCF then reinstalling it, so the car definitely knows its there, though it sounds like it does as the TC light is flashing.

Do you know which pin the signal arrives on? is it getting through? is it leaving the receiver when you press the blipper?

Just some things to think on.  There is nothing that can't be fixed with a hammer😜😜
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I should have said that I don't have a key fob remote. So to my knowledge the only three ways it could start are:-

1. Engine started, with ambient lower than 5 degrees, and coolant lower than 77 degC
2. Timed climate set, and ambient lower than 16 degC
3. Manual start, and ambient lower than 16 degC

Indeed, unless any comes up with a better plan I shall find someone with diagnostics that can force a start.

Thanks, Jon.

Wot about Craig ? He's only 25 mins up the motorway from Weston. Can he not do diagnostics on it ??

I've had the same problem this Winter - was looking for a thread to post my solution on - here is as good as any I guess (sorry to drag up an old post though)

This may just be co-incidence I guess but I can only "say what I see"

I had the same issue as the OP no manual or timed start + in my case no FBH via remote. No clicking, no short term burn, zilch. Checked the fuse was OK and, the limited of my technical capabilities thus reached, resigned myself to cold winter starts.

Yesterday I had my windscreen replaced - had two bad cracks, one down the centre from top to pretty much bottom and then along the drivers side of the car; the other bottom left of the passenger side.

As I am eternal optimist, and it was freezing cold at 4am this morning, I gave the FBH one last try and to my astonishment, it worked via the remote!

Happy days, fingers crossed it remains that way. Anyone care to hazard a guess why it made a difference?

now you know it works just make sure your battery is a good one or you will be having a non start just like me at 4am this mornig lovely defrosted car tho

been there, done that

When I was busy diagnosing mine earlier this winter I learned the following.

I could force a start by unplugging the remote control receiver in the boot (hidden behind the metal mounting plate to the right of the rear fuse box) and then short out the live and signal pins in the plug. I believe these were the red/yellow wire and the green/white wire but you can check this on the wiring diagrams on the wiki.

I too had the symptoms you describe, just after I got the thing to work once, then it wouldn't react at all and it turns out it had overheated (with an air lock) and locked out. It can also lock out after 3 failed attempts to light so although you had fault codes read, it is possible it has tried to start on three cold mornings and failed every time then locked out. I ended up buying an IID tool so I could see what was happening. Best thing I did, especially as there seems to be a ready second hand market for them on here so it is not such a big investment in the long term.

Third thing I learned is they will not work at all if the k-bus line on the 6pin plug on top of the unit is disconnected. This is not the same on all versions of the Webasto but does apply to BMW/LR versions and this fooled me when I was trying to test the heater on the bench.

Hope this is some help....... Taking a rest from Land Rovers for a bit.......