Wiring advice and best practice. Tow Bar, estate.

[stewlewis]

I bought a Witter bar off Ebay, which I've had fitted.
It came with a Westfalia wiring kit, it has a box of tricks, I thinks it's dedicated, semi, as it has a few spliced wires. It came of a hatch I'm installing to a ST.

I need to find a CAN wire in the rear compartment, there's enough to choose from but; How do I identify a CAN wire?
The instructions say GN but says to check. How would I use a multitester to I.D. a CAN?

I have an orange, switched IGN live to find, for the box'o'tricks and 13pin fridge relay. (soldered together already).

I have BLK/RD to splice into STOP wire. The instructions say WHI.

AND, I have 3 thicker LIVE wires that have been cut, they have mini fuses attached.
Continuous live to pin 9
Ignition switched live to pin 10 (via relay for fridge)
Power for the Westfalia box'o'tricks.

Would best practice be spicing in, via solder/heatshrink all three to a live feed I can find, of thicker wire?

OR in the rear fuse board:

1 Central locking system, Power tailgate
2 Trailer module (I have a 40A fuse in here)
3 Trailer module (empty, larger sized fuse)
4 —
5 Trailer socket (empty, mini fuse)
6 Steering wheel heating
7 Rear power windows
8 Trailer socket (empty, mini fuse)

Would I be better off using 3 circuit addition fuse taps for my lives from those empty sockets off the rear fuse board?
I was thinking 3.Trailer module, to box'o'tricks, 5&8.Trailer socket to the cont live and fridge pins.

The Westfalia instructions say NOT TO Vauxhall update.

Thanks in advance.

[cmor]

I have the instructions for the Westfalia kit if you need them.

The canbus wire on mine was connected to the green at the trailer module box, and also the white stop wire was there as well.
The best option is to use fuse taps to the rear fuse box.

[stewlewis]

Ah great.
I've downloaded the instructions for my kit (hatch) and my car (ST) between the two I believe I've sussed it.

So the box in the rear below the fuse board is a trailer module? What function does that serve?

The Westfalia instructions say GRN and WHI for CAN ans STOP, I can trust them then?

Would there be a switched live on a fuse board?
Trying to do as little splicing as possible, that would leave just STOP.

I guess using the add-a-circuit taps in the fuses mentioned would be safe current wise as the fuse board has two real thick cables feeding it.

[cmor]

With the VX towbar kit, the rear lighting module is replaced with a trailer module, same thing really just a few extra wires. The Westfalia kit can be spliced with the wires going into the small rectangular plug on the lighting module.

The rear fuse board has some very heavy supply cables so you can tap into the fuses there. I'll have a look at mine tomorrow and let you have the fuse numbers.

The Westfalia kit doesn't normally come with a power relay for the charging circuit, have you got one?

[stewlewis]

Yeah it has a relay, I thought strange as its not on the instructions. Its live via inline fuse and its earth to the 13pin. Switched via orange spliced to main orange to Westfalia box. Thought it was just a different version or something

[cmor]

Here's a photo of my rear fuse board:



I used a voltage sensing relay from Ryder towing for the power circuits - it saves trying to find a switched live feed as the relay does the work.

[stewlewis]

Nice one, thanks very much. I'll get on it this weekend, once I find a brick n mortar shop with wire/fuse taps without a 500% markup.

[stewlewis]

I did it, the empty fuse slots in the box weren't even wired behind so the idea of using spares went out of the window.
I picked up some add-a-circuit taps, they wouldn't fit in securely so I scratched that idea.

I ended up adding a 4 way fuse box from Halfords, tapped off the whi/red big connector at the bottom of the fuse board, permanent live.
To:
Red - Constant live - trailer pin 10. Cravan electrics can share car battery power.
Red/Blu - constant live to the Westfalia CAN box
Yellow - switched via an relay/ignition for fridge - trailer pin 9. The fridge only draws from car when hooked up and ignition on.

The loom had three inline fuses all running to a perm live I guess as they were cut, I just wanted a neater solution, hence the 4 way fuse box. I soldered on side of connectors all together for live in and I have 4 fused permanent live outs (One spare now) which I soldered into the spades and heatshrinked.

I struggled to find the correct wires in the locations from the Westfalia instructions, internet researching and some PF Jones instructions pointed me to:

Purple/Grey for switched live. (although this seemed to read 11v with ignition off, with ignition on it does actuate the relay.
Light Green - CAN bus. There were a bunch of greens, I tested it and saw voltage fluctuations, I spliced and hoped.
Purple/White - STOP brake lights.

All in the big bundle under the main rear fuse board.

The car ran OK, lights tested OK and wired up to the 'van all tested OK too. The car recognised the van and notified me the parking sensors were deactivated. I don't know about any stability programmes being activated, and I forgot to test if the power rear tailgate was deactivated too.

Saved a few quid, happy with the result, and the cost.

TowBar, Witter detachable and swan neck, with fold up 13pins skt. Dedicated Westfalia wiring kit, from hatchback. Ebay £106
TowBar fitting, and tyre rotation. Local chap £50
Wiring accessories, Halfords £19

PF Jones wanted £380 for the kit, exclusive of fitting.
TopFit wanted £513 for the same kit fitted.

[TMK-MARINE]

HI STEWLESS,
I'm new to this forum, trying to resolve a wiring problem. I have a 2017 estate and not able to identify wiring to the right side indicator and fog light.

I read much of your posting with interest which helped me complete some of the wiring for a 13 pin socket, only have two wires to complete which is causing me a head-ache. Can you advise how you managed to connect wiring to the right side rear indicator and fog light ?.
The main wiring for lights to the left side were straight forward splicing into the harness located next to the rear fuse board, but have not traced wiring to the right side lights.

Removed right side light cluster and confirmed colour of wires for / H Indicator (blue) and fog light (grey), but could not trace wires though loom to multi connector on left side next to rear fuse board.

Any help would be greatly appreciated.

Regards,
Tom