Ignition Live Under Passenger Seat - How Its Done -

[Dellmassive]

Ignition Live Under Passenger Seat - How its done -



This question pops up fairly often so i thought i would look at it a bit closer. . . . .

If your van was factory fitted with the AUX battery under the seat, then your sorted. There is already a feed under there . . . . =]

BUT what if your van hasn't got the Factory option? . . . . Well there are two options for you.


Run (a new wire) the factory wire from the BCM under the dash/steering wheel

or

Run a (a new wire) from the ignition feed center-line of fuses in the under dash fuse panel.


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lets look at the first option #1

The factory setup has a trigger wire that connects the BCM to a relay under the seat, which in tern connects the AUX battery to the front SA fusebox > VW T6 Fusebox - Fusebox/Fuse Chart SA - Primary Battery Fusebox
Now this feed is not an ignition feed as we traditionally know it, it used to be called "X-relief " as its only switched on when the BCM sees a RPM signal from The ECU. So it kicks in and out during start stop events.

this can be seen here:

.

Lets look at the diagram:



download a copy credit: @Loz here> Second battery wiring diagram

You can see that the BCM(J519) has a wire pin in connector T73a /3

its a sw (black) 0.5mm wire core that runs from the BCM under the central cable tunel and up into the seatbase. This is the BCM switched +12v signal when ignition is on and rpm is detected.

This connects to the factory 12v relay (J7) at pin 3, the relay has a perm 0v ground via J7 pin4 (brown wire 1.5mm down to the earth point under the seat base)

If you just needed the ignition feed then thats it . . . . .But if you were fitting an aux battery/relay or DC-DC charger then you need to fit the heavy duty +12v feed cable also.

in the factory setup its a 10mm red cable fed from the SA Fusebox under the starter battery, fed via an 100A supply fuse SA2, REMEMBER you need to fuse BOTH ends of the cable !!! so VW have added a 80A fuse under the seat base to protect the cable from any issues heading back toi the engine bay.

another thing to not is the VW relay is 100A rated.

the factory setup can look like this:

or this:

here is the Factory cable install for the 10mm feed cable . . . . . >
Tpi 2046279, T6 Repair Instructions For Voltage Supply Of 2nd Battery

here is a great guide from @travelvolts Electrics | Travelvolts > https://docs.wixstatic.com/ugd/d959f6_e84b43c19cce424e90952d456c91f103.pdf

and here > Installation Guide for Redarc DC-DC Charging Kit

more info over here > Stop/start...regen...smart Alternator... Dc-dc Charger For Leisure Battery Or Not?

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So what about option #2 . . . . . well this will give you a more traditional "ignition feed" the BCM supplys the SC fuse box with a +12 supply when the ignition is switched on.

credits to @Loz for these:

here > VW T6 Fusebox - Fusebox/Fuse Chart SC - Lower Dash Fusebox Listings

here > VW T6 Fuse Boxes - Overview Of Fuse Holder Vehicle Locations

here > Fuse Card

you can add new fuse terminals into any blank center fuse holder to addin a new circuits, this is the preferred more professional way of doing it, but dont go crazy with the amps, i would limit the circuits to 5A or 10A (unknown/untested max additional circuit loading to center line SC fuse-box)

you can buy the crimpon fuse terminals from the shop > Four Genuine Volkswagen Crimp Connectors For Stereo Quadlock / Fusebox

or buy the VW repair wire which comes with a length of yellow wire attached so you can just clip in and join the wire.

like these . . . .




another popular method is the piggyback fuse adapter as seen here>

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So what about all those existing connectors under the seat . . . . . . one of those must be ignition fed?

NOPE !! see here > Ignition Live Under Passenger Seat

as @Deaky said early on there isnt!

all the mid loom connectors at the bottom, which will be the rear PDC loom, rear lights loom, rear doors loom, rear ABS and brake pad also passenger seat loom,

here:

.

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There is no "No Dedicated Switched Ignition Live Under The Seat" - You Need To Run A New Wire From fuse-box . . . (if you want a separate 12v live when the key is on the accessory position your need a new feed from the center line of the under dash center fuse box.....)
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FYI - (yellow colour plug)

(Green) wire is T17f /9 - G46 Rear left speed sensor (do not connect to this)
(black) wire is T17f /10 - G46 Rear left speed sensor (do not connect to this)
T17f /2 - ABS - (do not connect to this)
T17f /3 - ABS - (do not connect to this)

T17f /8 - F11 Rear right door contact switch - (do not connect to this)
T17f /4 - F10 Rear right door contact switch - (do not connect to this)

T17 /11 - (white) G34 Front left brake pad wear sender - (do not connect to this)

T17 /12 - MX4 Right tail light - (do not connect to this)

.

..


**************************************************************************
There is no "No Dedicated Switched Ignition Live Under The Seat" - You Need To Run A New Wire From fuse-box . . . (if you want a separate 12v live when the key is on the accessory position your need a new feed from the center line of the under dash center fuse box.....)
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FYI - T17q (black colour plug)

T17q /1 - G203 Rear left parking aid sender (do not connect to this)
T17q /2 - G204 Rear centre left parking aid sender (do not connect to this)
t17q /3 - X68 Positive connection (parking aid), in rear bumper wiring harness (from J446 PDC) (do not connect to this)
t17q /4 - 352 Earth connection (parking aid), in rear bumper wiring harness (from J446 PDC) (do not connect to this)
t17q /5 - G205 Rear centre right parking aid sender (do not connect to this)
t17q /6 - G206 Rear right parking aid sender (do not connect to this)

.






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more info can be found here:

Installing 12v Socket /s - How Its Done -
.
12v Igntn Feed + 5xusb Charging From Ign Feed - Today's Install
.
12v Aux Feed + 5xusb Charging From Aux Battery - Today's Install
.
Led Rear Interior Lights - How I Done It.
,

Dellmassive`s -- "how I Done It" -- Thread


cant download the VIP docs....? come and jaoin T6F and become a VIP > VIP Membership | VW T6 Forum - The Dedicated VW Transporter T6 Forum


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work in progress.

T17-P RED conector under seat:
T17p 17-pin connector, red, under seat on front left



1 - wht/grn
2 - or/brn
3 - or/grn
4 - vil
5 - grn
6 - blk/blu - res heat relay
7 - rd/blu -
8 - brn
9 - or/br can?
10 - or/blk can?
11
12 - br/vi - v386
13
14
15
16
17 - rd/yel SC46 - j364 aux heater unit











End.

 

[travelvolts]

Not quite correct Del, X relief was on with ignition but dropped during cranking. The BCM output is a true engine run signal.

 

[MarkW-T6]

Hi. Just started to convert my newly purchased 2016 T6 Highline, 140, 6 speed, Bluemotion (no Ad Blue). Bucket list thing

Your info above is very useful so I wonder if you could help with a couple of things. I have a red cable under the passenger seat, presumably the 10mm you mention above. It is connected to a smaller cable which supplies the top cig socket on the dash. My intention is to connect the larger cable, via a 30A fuse and ign switched relay to a Ring RSCDC30 to supply/charge a leisure battery. Again, from your info I now believe none of the other cables under the seat are supplied via the ign circuit so will have to source this from the fuse box in the front footwell below the gear stick?

So, do I need the relay or will the Ring unit manage the connection from the starter battery sufficiently to prevent it from going flat? Is the Ring unit ok? I have read on the forum of issues with the solar switching, do you know is this resolved now as I intend to fit a solar panel. The info I have found on the Ring suggests that 4mm cable as minimum should be used for the battery connections, do you think this is big enough? Also can a battery charger be fitted with the Ring unit to be used with a 230v hook up? Any information & help would be greatly appreciated.

 

[travelvolts]

You don't need an ignition supply for the Ring but you will need to fuse it at 40 amps, not 30! Use 6 mm cable to connect to the leisure battery. Fitting a mains charger is not a problem. Connect the output from it directly to the leisure battery. Has the switching issue been resolved? who knows? Personally, I wouldn't touch 'em with a Barge pole!

 

[MarkW-T6]

Thank you. So if I terminate the existing cable at a 40A fuse I can then use 6mm to the split charger and back to the leisure battery. Same size for the ground? I’m assuming I can use the ground point available under the seats for input to charger and also for leisure battery I.e. I don’t need to pick up from starter battery. What would you recommend if not the Ring, C-Tek? Needs to be compatible with the stop/start system and accept solar input if poss? I have seen something I think from C-Tek, that has a battery charger and it all somehow links together, monitors batteries etc.

 

[travelvolts]

There are plenty of alternatives to the Ring. My personal favourite is the Ablemail, it is also 30 amp rated (min) and is available with or without solar input. The Ctek is only 20 amps but has a solar input. They are all compatible with T6. Whatever you decide to go with you can use the wiring as you say. You will also need a fuse at the leisure battery +

 

[andys]

But don’t get the Ctek thinking you won’t need a solar controller, the maximum voltage it can handle is only about enough for a 100-150W panel, which isn’t enough.

 

[travelvolts]

The voltage and the wattage are different considerations. It will handle a 150 watt panel comfortably but the Ctek is limited to a maximum panel voltage of 23 volts. There are plenty of panels around that have VOCs of less than 23 volts. High voltage panels are usually designed for domestic or industrial applications.

 

[andys]

I haven’t seen a panel over 150W with an open circuit voltage lower than 23v. My 250W panel frequently goes over 37v. I don’t see any point in going for below 150W in this country, there’s just not enough solar power available to charge what most people need in van, unless you only use it on sunny days.

 

[travelvolts]

No, there isn't much above 150 but most conversions are happy with a max of 150. No point producing more than you can use or store.

 

[andys]

No, there isn't much above 150 but most conversions are happy with a max of 150. No point producing more than you can use or store.

I suppose it depends on how much you need, but I make use of mine, and demands on power are only likely to increase. I’d turn it around actually, you SHOULD produce more than you need initially, otherwise you have no future-proofing. It’s better to start off bigger than to have to pay again to replace it in 12 months time.

 

[MarkW-T6]

Ahh! This was something I was unaware of, VOC? I was only looking at the wattage. The main use for the van is going to be day use, but will be as full a conversion as I can manage I.e bed, kitchen etc. I was only looking at 100W panels. The only use would be as a means of maintaining the battery if stopped somewhere for the day, probably just running a cooler or fridge. Not planning wild camping or anything like that. Thanks for the input and information though, I am a lot wiser now and will look a lot closer at the panels before buying.

 

[andys]

Ahh! This was something I was unaware of, VOC? I was only looking at the wattage. The main use for the van is going to be day use, but will be as full a conversion as I can manage I.e bed, kitchen etc. I was only looking at 100W panels. The only use would be as a means of maintaining the battery if stopped somewhere for the day, probably just running a cooler or fridge. Not planning wild camping or anything like that. Thanks for the input and information though, I am a lot wiser now and will look a lot closer at the panels before buying.

My main point really is that a 100W panel does not give you 100W so don't use that figure when calculating your needs. Saying that, stopping somewhere for the day and then driving again later, without wild camping, you probably don't need a solar panel at all. But good to plan for future-proofing by buying equipment that will let you add on to it later, instead of starting from scratch. I know cos I did, pretty much everything has had to be upgraded in mine, I could have saved a fair bit by spending a bit more in the first place and buying bigger.

 

[travelvolts]

I suppose it all comes down to whether you want a camper van or an exercise in how much tech you can cram into a vehicle. I agree, in the OPs case he probably doesn't need a solar panel at all as long as he has a decent DC-DC charger but I always say that having at least more than one charging source is a good thing as you never know when one might fail or become unavailable.

 

[MarkW-T6]

Thanks guys, having taken on board your comments I am going to go with the Ctek 250SE. I know I’m probably over engineering the spec but have a bit of time on my hands at the moment. As said, this is a bucket list thing and just want to get it something like from the outset, don’t want to be constantly changing or adding kit. It very probably will become an over specced day van!! I’ll revisit the solar panels using the new info you have provided to find something suitable for the Ctek.

 

[travelvolts]

https://www.travelvolts.net/shop
https://www.travelvolts.net/shop-14

 

[MarkW-T6]

Thanks. I'll be placing an order at the beginning of next week.

 

[Nic Price]

With regards to the ctek 250se can anyone tell me the red cable that goes from the ctek to the fuse box which fuse they have it going to.

And the black cable next to that red cable on the ctek does it need to go to earth.

Ta..

 

[Deaky]

The red cable is to identify a smart alternator. If you have one (on a T6 you do). Connect it to ignition live. And fuse in the centre row of the fuse box will give you this. The black cable is used to identify the type of leisure battery you have. Leave it disconnected for lead acid or ground it for AGM

 

[travelvolts]

Towards the top of the centre column there will be some empty fuse ports. Use one of those and then you are sure to avoid upsetting any vehicle circuits. Be sure to insert your fuse adaptor (if using one) the correct way round as there will only be one pin in the fuse port. Cable from fuse adaptor should exit facing the passenger side.