backinblack · Jan 30, 2021

Are you priming the pump or testing it from the diagnostic screen?
I could test the pump circuit on the bench by using a bulb instead of the pump you can see it flash.

biketeacherdave · Jan 30, 2021

This is all on the work bench at the moment. The fuel pump is connected directly to the test battery earth as is the fbh.
I can activate the fuel pump using the software so I know that's all good.
I no longer own a scope so cant trace canbus on pin2.
I can pull the unit off the D3 and connect it up to this unit and push a w-bus signal on pin 2 if I need to just to see what happens.

backinblack · Jan 30, 2021

If everything passes the test and you get the red FD led on doing glowpin test I reckon you have a good unit but it needs to talk to the car.
I haven't scoped it on the car but on the bench the FBH sends out 12v which drops at regular intervals creating a -ve pulse with respect to the 12v, I was told that the car grounds this signal (presumably in a specific pattern creating a +ve pulse ) as a response. IMO that the D3 FBH will also send 12v with a -ve pulse so would not respond to the L322 FBH with the right message. I think you need to find a way of connecting pin 2 to the car.

biketeacherdave · Feb 2, 2021

Yes black I'm sure your correct. My car should have the plug fitted somewhere to talk to the fbh BUT iv got an analogue board comming this week to completely by pass the issue.

I'm still going to find away around the issue with the original board for future reference. My research suggests shorting pin 3 to earth will fire it up. Iv nothing to lose doing it iv found the webasto installation pdf and it clearly shows this if installing the unit to work off a switch.
There are x2 main fbh units with part numbers on 1st one says pin1 +12 volts to activate the other part number says ground pin 3. Of course the part number on mine is different

backinblack · Feb 3, 2021

@biketeacherdave I'm sure the analogue board will sort the issue of needing to talk to the car.
Are you intending to use it as a parking heater? if so how are you going to activate the fan on the heater matrix?

biketeacherdave · Feb 3, 2021

Both parking and engine warmer to help the lpg along this time of year.
Iv recently had a fsr fault which actually turned out to be the +12volts connection in the plug to the fsr. Iv got a new fsr and plug sitting here. The reason the +12v pin has burned out is because the fsr has been replaced before and not fully pushed home meaning it wasnt in the cool air stream properly and over heated the plug.
When I can get under the dash to cut the old plug out and solder in the new I'm going to have a play around and see if I can get it to fire up the fan motor directly by putting 12volts on it.
Fingers crossed .
Mite even try adding a switched 12volts to the relay pin in the fuse box

backinblack · Feb 3, 2021

Don't know if you've checked the diagram or not. The only one I have for the older model is for the 2003 LHD V8 but probably still valid and it does show a connection to the HEVAC
Looking at the diagram it shows a K-BUS signal which I have still to learn about but would imagine it's not just a 12v feed.
It sounds like you're getting closer to a solution though

biketeacherdave · Feb 3, 2021

Pulse generator.

Going to try one of these they put out a square sine way going to see if I can fool the fbh with this, it pretty much matches the can bus.....I hope

backinblack · Feb 3, 2021

found a 2001 diagram from fulfatrr but almost the same.
I suppose the signal generator is worth a try for a few quid but given the Webasto software must send different commands to test each component IMO it's can't be a fixed wave pattern, it must change depending on what the software is asking it to do.

biketeacherdave · Feb 3, 2021

Even if I find the 6 pin plug and it all works via the onboard computer/TV screen it wont work as I really want.
The analogue board will just switch on/off at the press of a button

Stuart Sutton · Jan 19, 2022

Hi , Just been reading this thread and found it very interesting. I've retro fitted a Webasto TTC to my D2 , I have it coming on 3 different ways , 1 by just starting the engine , 2 via a cheap remote really, or via a switch that I've mounted under the cruise control switch on the dash clock surround. It works well gets up to 72 degrees quite quickly then in goes in to half power mode . I've had a few issues recently with it , the combustion fan failed to got a reconditioned one off Ebay, then it was smoking too much which turned out to be the foam filter in the intake pipe being too restrictive (mine is out of a Rover 75) then it was taking an hour to get to 41 degrees so I chucked the cheap Chinese fuel pump in the bin and fitted a Genuine Webasto pump. The next job I want to do now it wire it into the Climate Control unit. I must add when I first got the unit from a Rover that was in a breakers yard the heater wouldn't work , so I sent the PCB off to be repaired by French Mike I found him via the Rover 75 forum.