Rear fog lights not operating [Resolved]

[Tony Phillips]

My 2017 T30 lwb has just failed its MOT on inoperative rear fog lights, the bulbs are ok I've tested them,obviously no supply, the switch doesn't light up and the Icon on the dash doesn't light. I have downloaded the fuse card from the Forum but am unable to find a specific fuse for the fog Lights, can anyone point me in the right direction please, I have even tried another switch just to rule that out. Any Help greatly appreciated.

 

[Dellmassive]

can you post a pic of your SC fusebox?

the lower dash one.

lets see what you have.

 

[Tony Phillips]

Will this do?

 

[Dellmassive]

yes . . .

take this one out and have a look at it . . Blue 15A. (post a pic also)

 

[Dellmassive]

SC12 shown here - T6 - Fuse Card

detailed here - T6 - T6 Fuse Layout SC,SD,SF (NON-CALI)


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.

 

[Tony Phillips]

I've just checked, That 15amp fuse is intact, all other lights are working. When I pull the switch out to turn on fogs front works but rear doesn't , it neither lights up switch or on dash, thats why I tried another switch. Confused

 

[Dellmassive]

on my light switch.

i have to manually turn round, then pull out two stages.

first stage is front fogs,

second stage is rear fogs + dash fog light indication.


is yours the same?

 

[Dellmassive]

re electrical issues. . .

one thing is to check EVERY FUSE !!! as sometimes more than one fuse can feed a circuit,

or a different fuse is connected to what the fuse chart state.

another thing ., . . . the lights are BCM controlled and monitored.

so you can try a BCM reset - [Guide] Full Van ECU Reset (Capacitive Discharge) -- How I Done It --

which rear lights have you got?

The T6 Vehicle SSP-561

VW Self Study Programme, Document 561 - The T6 2016 Benchmark in its class Pioneer in the segment for more than 60 years The totality of all the product characteristics ascribed to the Volkswagen Transporter has made it the epitome of its...

www.t6forum.com

...

 

[Spaghetti]

Also, I have a tow bar and if it thinks something is plugged into the tow bar, it disables the rear fog(s).

Worth checking this if you have a bar.

 

[Tony Phillips]

Sorry for slow response. The switch is the two stage. Fronts work rear doesn't.
Tail lights are as top left barn door standard.
Tow bar fitted but nothing plugged in and been blasted with contact cleaner and air line.
I've checked all the fuses I can see with multi meter.
Totally baffled

 

[Newf]

My 2018 had the same issue on its first MOT last year. Thinking it would be simple enough I told the dealer to sort it out.
Several hours and about £600 later they found a broken wire. If I remember right the cable passes under the passenger seat then towards the BCM i think. I must have disturbed it at some point soundproofing etc. Decent auto electrician would probablly have sorted in ¼ of the time for £100.

 

[Dellmassive]

So possible cable fault...

Ill double check this, but from memory.......

The setup is.

Power to BCM.
Ground to bcm.
Light Switch input to BCM.
Dash icon output from BCM.
Light output from bcm.

Then cable run is.
From bcm to underseat join conector.
Then middle loom from seat base,
up B pillar.
Allong passenger roof line.
Down d pillar to rear join.
Final loom d pillar to light clusters.
Common ground at rear of van.

 

[DXX]

Have you recently had a pop top fitted?
There have been cases of wiring harness damage near the roof on the nearside caused by poor installations.

 

[Dellmassive]

wire route -




...

test mid point here -

T17n-4 : 17-pin connector, light green, under seat on front left

gr/ws - grey/white wire



test if power for fog light is coming from BCM,

test if power gets to midpoint connector,

test continuity from midpoint connector to rear cluster

test rear ground.

Reset BCM.

check all fuses.

....




.



cable route . . .

B = BCM under dash via cable tunel under mid flooring to seat base.

coupler under seat base,

D-Pillar to rear via red route to rear cluster.

link between clusters across D-pillar arch.

 

[Loz]

Need to invert that picture so it becomes a right hand drive version

 

[Dellmassive]

I don't even think it's a T6 pic. . . .

In wiffs of T5 to me looking at the indicator wing repeater.

Edit.... Fuel flap?

 

[rover220]

Tow bar fitted?

 

[Spaghetti]

I don't even think it's a T6 pic. . . .

In wiffs of T5 to me looking at the indicator wing repeater.

Edit.... Fuel flap?

Looks like a T5 test mule

 

[rod_vw]

My LWB T6 also has a multi-pin connector at roof line above the D post.

Another thought, if there is a genuine tow bar fitted could there be a fault in the tow bar module under the left front seat or even will that give the same fault if it's fuse is blown? Just musing it over.

 

[Tony Phillips]

Have you recently had a pop top fitted?
There have been cases of wiring harness damage near the roof on the nearside caused by poor installations.

No Pop top, Its a working van as well as my daily.