D+ signal fuse

[Phil Saunders]

Hi,
I'm looking for the D+ signal fuse, is it called something else on the fuse board? Is it the onboard signal unit?
Thanks

 

[Pauly]

D+ is normally the term given to the alternator output, its similar to ignition live but actually needs the engine running rather than just the key on to go live, most people would just use an ignition live if your just looking to trigger something

What are you trying to do ?

 

[Phil Saunders]

D+ is normally the term given to the alternator output, its similar to ignition live but actually needs the engine running rather than just the key on to go live, most people would just use an ignition live if your just looking to trigger something

What are you trying to do ?

Hi Pauly, thanks for taking the time to respond. I'm installing a clayton power LPS 3000 but I've found the fuse now so all good thanks

 

[Raul a/3]

Hi Pauly, thanks for taking the time to respond. I'm installing a clayton power LPS 3000 but I've found the fuse now so all good thanks

Can you share please the location of said fuse?

 

[Phil Saunders]

 

[Phil Saunders]

this photo was sent to me by Marc at Ahoy Leisure who sold me the Clayton LPS 3000 and is a very helpful guy. i would recommend them.

 

[rod_vw]

I trust that you are all aware that a VW/MAN equivalent of a D+ signal and an ignition on signal are two very different things as @Pauly has said above.

Ignition on is just what it says on the tin.

The signal that VW/MAN use comes from the BCM (Body Control Module) T73c Pin 72. It is my understanding that this pin is energised when the alternator is charging but can be de-energised when more important current consumers need the alternator output i.e. Load Shedding. The function of this circuit is configurable in the BCM coding with VCDS or similar software.

This is how VW/MAN connect a second battery to charge controlled by the Second Battery charging circuit relay (J713). The controlling signal comes from the BCM via the Red/White wire connected to T2lk pin 1, The brown wire connects to chassis ground (-ve)

Here is the BCM (J619) end of the circuit, controlling signal is via the Red/White wire from T73c Pin 72.

 

[Graeme]

D+ is normally the term given to the alternator output, its similar to ignition live but actually needs the engine running rather than just the key on to go live, most people would just use an ignition live if your just looking to trigger something

What are you trying to do ?

HI Paul i have a man tge and also so have a clayton which please is the d+fuse thanks Graeme

 

[Tattyhobo]

View attachment 666

Hey guys.. sorry for being dumb.. I’m trying to fit a victron dc dc charger. Once you found the d+, did you use one of these? (pic) If not, can you please tell me how you used that fuse port? Much appreciated!
Btw mine is 2023 Crafter MWB 4motion.

 

[Jaywesty]

Hi guys I’m about to install a Clayton is the above picture the correct one for a my25 van aswell?
I need to find the d+
It it in the fuse box under the passenger seat? Or a different fuse box
Many thanks

 

[rod_vw]

Hi guys I’m about to install a Clayton is the above picture the correct one for a my25 van aswell?
I need to find the d+
It it in the fuse box under the passenger seat? Or a different fuse box
Many thanks

It isn't a D+, it's an ignition switched live that you will find under the left front seat.

The real D+ comes direct from an ECU which will not have the connection either coded in or wired if your vehicle came from the factory without a second battery.

However most of us use an ignition switched live to control Victron B2Bs etc. without any problems if the B2B is correctly configured.

 

[Raul a/3]

Can you share please the location of said fuse?

There isn't one, unless somebody prepared one in advance as per @rod_vw post above.
I have used ignition life found under tbe passenger seat. I fed that to the B2B H terminal, disabled the engine detection function, and set starter voltage lock out at 12.2v with 12.4v resume.
Works like a charm, also I have a inline switch in the ignition live feed to switch off B2B when not needed; those times when solar is plenty.

Faster fingers above already answered .

 

[Jaywesty]

It isn't a D+, it's an ignition switched live that you will find under the left front seat.

The real D+ comes direct from an ECU which will not have the connection either coded in or wired if your vehicle came from the factory without a second battery.

However most of us use an ignition switched live to control Victron B2Bs etc. without any problems if the B2B is correctly configured.

Thanks rod my van has the second battery from factory,
mark at ahoy who supplied my Clayton mentioned the d+ im not massively confident on electrics hence buying the Clayton system so should I just look for a switched live ?under the pass seat?
Many thanks Jay

 

[rod_vw]

Hi @Jaywesty if your van was fitted with a second battery from the factory that will be under the bonnet. That is connected / charged via a relay {J713}, which in turn is operated by a signal from the Onboard Supply Control Module (previously often called the Body Control Module) which lurks high up above the driver's feet under the dash.

I'm afraid I cannot be sure where this relay is on your van but I would suspect that it is in amongst the items behind the second battery. To identify the relay I believe it will have two very thick black cables, one small brown and one red/black. The red/black is the D+ from the Onboard Supply Control Module.

 

[Jaywesty]

Thankyou rod.
I’m hoping to use a switched live i should probably check with Clayton if this is ok??
Much appreciate your input thank buddy

 

[rod_vw]

Thankyou rod.
I’m hoping to use a switched live i should probably check with Clayton if this is ok??
Much appreciate your input thank buddy

Yes that is wise. Also ask them and / or whoever wired the new battery circuitry if the old (factory) split charge relay should have been removed. Normally when the factory basic split charge relay system is replaced by a B2B unit the split charge relay becomes redundant and is disconnected / removed.

 

[Jaywesty]

Yes that is wise. Also ask them and / or whoever wired the new battery circuitry if the old (factory) split charge relay should have been removed. Normally when the factory basic split charge relay system is replaced by a B2B unit the split charge relay becomes redundant and is disconnected / removed.

Cheers rod it’s a brand new van with factory 2nd battery so I don’t know about that tbh…
.the Clayton LPs I’m fitting has a small blue wire (like a blue amplifier switch on wire from back in the day!
that goes from either a d+ or after speaking to them a cranked live or engine run positive ...i was advised.

I found quite a few tbh a few empty ones without fuses that had a switched live also so im hoping one of these will work?
I thought from watching the Clayton installation videos ahoy put up this would be a simple task, but I have messed about all day trying to run cables into the front footwell battery without disconnecting the driver and pass seats through fear of throwing lights up on the dash .
.give me mechanical and bodywork any day over electrics on a new vehicle.im used to restoring old defenders so this isn’t my strong point at all the advice you’re sharing is invaluable

 

[rod_vw]

I'm not committing myself 100% certainly without seeing the Clayton kit. However from what you say a connection via a 'piggyback fuse' fused at no more than 3A installed to one of the existing fuses under the left front seat that becomes live when the ignition is switched on will do the job.

If you disconnect the big red (17 way) connector under the seat and switch on the ignition you will almost certainly have an airbag failure warning on the dash which will require plugging in some type of diagnostics kit to re-set. I don't know where you are but if you are a member of the T6 forum you will almost certainly find someone on there reasonably local to you who can re-set this for you with VCDS or similar. Local dealers will do it for you but they want that dirty stuff called money for that!!

 

[Jaywesty]

I'm not committing myself 100% certainly without seeing the Clayton kit. However from what you say a connection via a 'piggyback fuse' fused at no more than 3A installed to one of the existing fuses under the left front seat that becomes live when the ignition is switched on will do the job.

If you disconnect the big red (17 way) connector under the seat and switch on the ignition you will almost certainly have an airbag failure warning on the dash which will require plugging in some type of diagnostics kit to re-set. I don't know where you are but if you are a member of the T6 forum you will almost certainly find someone on there reasonably local to you who can re-set this for you with VCDS or similar. Local dealers will do it for you but they want that dirty stuff called money for that!!

Thankyou for the advice rod
It really is appreciated .i have a carista but have not used it yet so if i don’t switch on the ignition hopefully if im struggling i can remove the seats out of my way and it won’t need to be used