FBH - diagnostics? (copy of thread from OC forum...) by theridler



Hi, I've been checking over my FBH (Fuel burning heater.)/ parking heater & all (now) seems well which is good seeing that weather is getting colder...

Now to the point of this - for about 2 years I've had a diagnostic tool for the FBH which I haven't got up and running yet. Thought that as I have it I should work out how it works and see what it does!

By the way thanks to HarryM1BYT & FrenchMike (from OC forum...) for their considered input in working through checking my FBH! My concern was just down to my FBH cutting in and out (went through maybe 3 power cycles during the default 1/2 hour parking heater operation by remote) - we worked out that it was just getting up to the77degC mark (which shuts down the FBH operating cyle...). Since then have used it twice in the mornings before my wife heads off to work at 7:30am and her report is that car is warm & toasty (no feedback on engine temp, but as she was heading off car seemed like it was up to running temp..).

Anyway back to diagnostic tool - please see attached photo.

Now for my questions :
Instructions say:
Download drivers & software. Install drivers & software (done).
Connect adaptor to PC/|Laptop (OK)
Use correct COM port (OK, COM4)
Connect red & black clips to battery (OK)
Connect the tallow clip to diagnostic wire in car (first question - I think this is pin 2 of 6 pin FBH plug, should I connect to pin on FBH or to wire from car?)
Select heater type in programme (second question - I understand from another thread that Rover option doesn't work & select Thermo Top C/Z BMW?)
6-pins connector is for reading FBH errors (third question - do I need to plug this in? Which would then make it difficult to connect the yellow wire because the FBH connector pins are now covered...?)
There is a small white push button on top of black box - this is to select which pin is used for diagnostics - in our case pin 2 (Fourth question - this point makes me think I need to connect yellow wire to the FBH 6-pin socket, pin 2...? Not too much of a problem - I'll either temporarily break this wire or put an inline switch in...)

Fifth question - with this all hooked up (with FBH still connected to car), I then start up FBH with my remote?

Last question - how would I use the 6-pin connector on the diagnostic tool (see second picture)? It has 2 wires RED to pin1, Blue to pin 2 and the yellow wire is also connected to this cable?

Any thoughts and comments would really be appreciated. Thanks....

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Posted 26 Oct 2016, 07:04 #1 

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I don't know what software comes with the tool. There is some Webasto SW around so I hope they aren't pirating that.

Diagnostics on the FBH are done via Bus. So I suspect they are giving you two options. 1 is to connect the 6 way direct to the FBH, the other is to connect to the diagnostics on the diagnostics connector using the croc clip. This is only guesswork though.

With the 6 way connected to the FBH, you can do a few things but you wouldn't be able to check the thermostat in the bumper. If I remember right, the Webasto software can activate the FBH using the diagnostics.

It might be helpful if you can figure out which pins the wires in the 6 way are in, and what the croc clip is actually connected to.

Posted 26 Oct 2016, 16:46 #2 

I think the pins in the 6 way are pins 1 & 2 which relate to the 2 options for diagnostics lead (in our case ... pin 2 which is what the yellow crocodile clip is for I have since found out).

Posted 26 Oct 2016, 17:33 #3