Guide: Hardwiring dual Dashcam in mk4 GS450h (Premier)

[i-s]

Today I installed (hardwired) a dual-channel Viofo A129 Duo into our GS450h Premier (with rear sunblind). 

This is a guide on how to do it, to save anyone else time figuring out the stuff I had to figure out. For starters, don't disassemble your boot!

I used the Viofo 3-wire hardwire kit (to enable parking mode). For this you need 2 add-a-fuse mini-blade fuse doublers. 

Front Camera

The front camera location is best near the centre-line. The GS screen curves, so anywhere off the centreline starts to point outward to the side instead of forwards. I placed the camera just to the left of the Rear view mirror base, as there's some sort of camera sensor on the right-hand side at roof level. Also our car has the AHB camera on the centreline.

From there, the two (power supply and rear cam) cables go up into the roof console, mainly to put the ferrite on the power cable somewhere. From there they run across the top of the windscreen, tucked into the headliner, to the A-pillar. The A-pillar is where things get a little interesting - there's no way you can tuck the cable at the A-pillar (and you wouldn't want to tuck across the top of the a-pillar anyway, as that would interfere with deployment of the curtain airbag). 

It is necessary to remove the A-pillar trim. Pull outwards at the top and it will come loose, but held by a captive clip (designed to prevent the trim becoming a missile when the curtain airbag deploys). You release this with a pair of needle-nose pliers, turning it to fit through the slot. 

You can just see the black head of the clip in the slot - it's tricky to photograph and tricky to get at. Once you've released that clip and the middle clip (just a push fit one) then you need to pull the trim piece up from the dashboard to remove the trim. 

Now you can run the wires down the A-pillar, along the sunroof drain tube (if fitted - otherwise that should leave plenty of space for your cables!). In order to do this most neatly, you need to go underneath the wiring connector you find there.

Now feed the wires into the gap between the door and the side of the dashboard:

This gets us to the passenger footwell, and onto our next section. When you replace the A-pillar trim, make sure you reinstate that top retention clip, otherwise it may interefere with the airbags. 

Power Supply

For a 3-wire kit you need a permanent 12V and a switched 12V. In order that this all be completely reversible (ie not require any soldering, stripping, etc of the cars wiring looms) I used Add-A-Fuse units. I connected into the passenger footwell fusebox on the connections for Night Vision (not equipped, but fuse is present...) (This is our switched 12V) and into the Power passenger seat (permanent 12V). For ground, there's a handy bolt. 

The easiest way to do all of this is to drop the trim panel in the passenger footwell - I didn't realise how easy that would be at first. Simply pull it out and down. 

The bolt head exposed nearest the door is your easiest ground connection:

And put your add-a-fuses into the locations described. 

That should cover power supply - note that you can not re-fit the fusebox cover with the add-a-fuses in place. 

Rear Camera wiring

You've already got your rear camera wire down into the front of the passenger footwell. Simply tuck the wire under the plastic trim of the door sill, and continue along, past the B-pillar into the rear footwell and along the rear door sill also. There's a tight spot alongside the front seat, but you can hide the cable away entirely throughout this section. 

Continue along and tuck the cable up the side of the rear seat

At the top, tuck the cable along the side of the parcelshelf, until you get to the rear blind. 

I was afraid that the rear blind was going to be very difficult and mean I'd have to go down into the boot and come back up (and I removed the boot trims to discover that this is pretty much impossible). However, it's actually trivial! 

Raise the blind, THEN feed the cable through, and tuck the cable down. The side track that the blind runs in doesn't continue much below the level of the parcel shelf and there's actually plenty of room to tuck the cable in!

You can then put the blind down, partially to check that it isn't impeded but also to finish the job. Place your rear camera and tuck the wire around the edge as normal. Note that you can't place the rear camera high up because the blind will hit it when raised. I placed our rear camera just to the side of the Chimsel (That's a word! Honest! Comes from CHMSL - Centre High Mounted Stop Light). 

Writing all of this made it seem much easier than it felt like! Replace the removed bits of trim, and all should be good. 

Please note that this is for information and entertainment purposes only. If you blow up an airbag or fry your car's electrics when doing this, it is YOUR fault. 

 

[Herbie]

Great guide I, well done.

[Farqui]

Nice write up that and well done for giving it a go yourself.

I had reservations about the rear blind too but in practice fitting the rear camera is a doddle.

[sudhir]

@ i-s

hello are you sure the NV-IR fuse is a switched fuse? I tapped into it and turned the engine on but there was no power to the camera? i connected just the ACC wire and Ground wire. Did not connect the red BATT wire to make sure NV-IR is indeed a switched fuse. any advice much appreciated

[sudhir]

On 1/13/2019 at 2:38 PM, i-s said:

Today I installed (hardwired) a dual-channel Viofo A129 Duo into our GS450h Premier (with rear sunblind). 

This is a guide on how to do it, to save anyone else time figuring out the stuff I had to figure out. For starters, don't disassemble your boot!

I used the Viofo 3-wire hardwire kit (to enable parking mode). For this you need 2 add-a-fuse mini-blade fuse doublers. 

Front Camera

The front camera location is best near the centre-line. The GS screen curves, so anywhere off the centreline starts to point outward to the side instead of forwards. I placed the camera just to the left of the Rear view mirror base, as there's some sort of camera sensor on the right-hand side at roof level. Also our car has the AHB camera on the centreline.

From there, the two (power supply and rear cam) cables go up into the roof console, mainly to put the ferrite on the power cable somewhere. From there they run across the top of the windscreen, tucked into the headliner, to the A-pillar. The A-pillar is where things get a little interesting - there's no way you can tuck the cable at the A-pillar (and you wouldn't want to tuck across the top of the a-pillar anyway, as that would interfere with deployment of the curtain airbag). 

It is necessary to remove the A-pillar trim. Pull outwards at the top and it will come loose, but held by a captive clip (designed to prevent the trim becoming a missile when the curtain airbag deploys). You release this with a pair of needle-nose pliers, turning it to fit through the slot. 

You can just see the black head of the clip in the slot - it's tricky to photograph and tricky to get at. Once you've released that clip and the middle clip (just a push fit one) then you need to pull the trim piece up from the dashboard to remove the trim. 

Now you can run the wires down the A-pillar, along the sunroof drain tube (if fitted - otherwise that should leave plenty of space for your cables!). In order to do this most neatly, you need to go underneath the wiring connector you find there.

Now feed the wires into the gap between the door and the side of the dashboard:

This gets us to the passenger footwell, and onto our next section. When you replace the A-pillar trim, make sure you reinstate that top retention clip, otherwise it may interefere with the airbags. 

Power Supply

For a 3-wire kit you need a permanent 12V and a switched 12V. In order that this all be completely reversible (ie not require any soldering, stripping, etc of the cars wiring looms) I used Add-A-Fuse units. I connected into the passenger footwell fusebox on the connections for Night Vision (not equipped, but fuse is present...) (This is our switched 12V) and into the Power passenger seat (permanent 12V). For ground, there's a handy bolt. 

The easiest way to do all of this is to drop the trim panel in the passenger footwell - I didn't realise how easy that would be at first. Simply pull it out and down. 

The bolt head exposed nearest the door is your easiest ground connection:

And put your add-a-fuses into the locations described. 

That should cover power supply - note that you can not re-fit the fusebox cover with the add-a-fuses in place. 

Rear Camera wiring

You've already got your rear camera wire down into the front of the passenger footwell. Simply tuck the wire under the plastic trim of the door sill, and continue along, past the B-pillar into the rear footwell and along the rear door sill also. There's a tight spot alongside the front seat, but you can hide the cable away entirely throughout this section. 

Continue along and tuck the cable up the side of the rear seat

At the top, tuck the cable along the side of the parcelshelf, until you get to the rear blind. 

I was afraid that the rear blind was going to be very difficult and mean I'd have to go down into the boot and come back up (and I removed the boot trims to discover that this is pretty much impossible). However, it's actually trivial! 

Raise the blind, THEN feed the cable through, and tuck the cable down. The side track that the blind runs in doesn't continue much below the level of the parcel shelf and there's actually plenty of room to tuck the cable in!

You can then put the blind down, partially to check that it isn't impeded but also to finish the job. Place your rear camera and tuck the wire around the edge as normal. Note that you can't place the rear camera high up because the blind will hit it when raised. I placed our rear camera just to the side of the Chimsel (That's a word! Honest! Comes from CHMSL - Centre High Mounted Stop Light). 

Writing all of this made it seem much easier than it felt like! Replace the removed bits of trim, and all should be good. 

Please note that this is for information and entertainment purposes only. If you blow up an airbag or fry your car's electrics when doing this, it is YOUR fault. 

 

hello are you sure the NV-IR fuse is a switched fuse? I tapped into it and turned the engine on but there was no power to the camera? i connected just the ACC wire and Ground wire. Did not connect the red BATT wire to make sure NV-IR is indeed a switched fuse. any advice much appreciated

[i-s]

If you're using the Viofo 3-wire power supply (that can enable parking mode) then you need your permanent live - this is the line that power is actually drawn from. The switched live (NV-IR) is actually only used as a signal to tell the camera when to wake up into run mode instead of parking mode. 

If you're not going to use parking mode (which, in the event, we don't) then you can simply connect both wires to the switch NV-IR live and the camera will behave as normal (come on with ignition, go off when stopped). 

[sudhir]

On 9/21/2019 at 6:02 PM, i-s said:

If you're using the Viofo 3-wire power supply (that can enable parking mode) then you need your permanent live - this is the line that power is actually drawn from. The switched live (NV-IR) is actually only used as a signal to tell the camera when to wake up into run mode instead of parking mode. 

If you're not going to use parking mode (which, in the event, we don't) then you can simply connect both wires to the switch NV-IR live and the camera will behave as normal (come on with ignition, go off when stopped). 

Excellent, that did help. I have viofo 3 wire hardwire kit. I also have normal fuse tap with cigarette lighter on other end...I have fitted the viofo one and set the cutoff point to 12.4v(so that the camera will turn off if battery  power falls below 12.4).. Many thanks for this write-up. 

[aviator888]

Sorry if this sounds a bit silly, but why did you go all the way to the passenger side dash? 

I doubt the small camera like this would draw much power, so it could of been wired into ambient light circuit just above the rear view mirror? 

[Herbie]

17 minutes ago, aviator888 said:

Sorry if this sounds a bit silly, but why did you go all the way to the passenger side dash? 

I doubt the small camera like this would draw much power, so it could of been wired into ambient light circuit just above the rear view mirror? 

But it's 12V up there and the camera works on 5V. Maybe there wasn't enough room to put the converter up there?

[aviator888]

It's just seems way too complicated.. 

Why would i want to find room for 12v to 5v step down transformer, removing pieces of trim with the risk of blowing airbags, damaging the trim clips etc.. ?

Simple camera that runs off 12V dc feed, wired into reading lights above. Job done. 

[i-s]

Because this has made no modification to the vehicle. It can be entirely reversed. It has not damaged or modified any of the car's wiring. 

[Herbie]

5 hours ago, aviator888 said:

Simple camera that runs off 12V dc feed, wired into reading lights above. Job done.

I may be wrong (I often am) but I don't know of any dash cams that are 12V. As far as I know they all operate on 5V with mini USB power connectors, which is why you don't have to change cabling if you change brand of camera. Plus the reading lights are probably permanently live as opposed to being ignition switched.

[Chris JJ]

I fitted my nextbase camera today, but didn't realise the supplied piggy back fuse would work as looked different from the lexus fuses in the fuse box. I even went to Halfords (a waste of time) to get one, then ordered the actual micro fuse piggy back fuse from amazon.

Anyway, then when I compared the prongs on the fuse and realised it would fit. A bit stupid of me, but just in case anyone else hasn't seen the micro fuses before hopefully my mistake might help someone else avoid it.

[Chris JJ]

I got the matching piggy back connector for the fuses arrived today

Link if anyone needs them they do seem a shallower fit, but the fuse box cover doesn't fit. £ 1.95 each including postage so seemed good value.

https://www.ebay.co.uk/usr/rich_remo

[develu]

Thanks for the writeup, that's useful, could you repost the images since the link is expried.