Where should I run cables through the 100 LC Firewall

Submitted: Monday, May 05, 2008 at 09:30
ThreadID: 57288 Views:13564 Replies:9 FollowUps:7
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I want to run cables through the firewall of a Toyota V8 petrol 2004 100 series GXL Landcruiser to an engel outlet on the passenger's side in the rear of the vehicle. I also want to run heavy duty cables to the rear of the vehicle to an Anderson plug for my caravan. The engel will be powered from the auxiliary battery of a correctly installed dual battery system.


Where is the best place to go through the firewall on the left hand side so that I do not risk damaging existing wiring or introducing interference or induced spikes to the car's electronic circuits/computers?
In the case of heavy gauge cables for the caravan is it best to go through the car, through the chassis or just tucked up out of the way under the car?


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Reply By: jdbb - Monday, May 05, 2008 at 10:28

Monday, May 05, 2008 at 10:28

I did this on the weekend. You've got me wondering if I've stuffed up because I ran 2x 3B&S cables down the drivers side of the cruiser (2006 TD). There appears to be more room in the recess under the sill panels down the drivers side.

There is a rubber grommet with cables going through the fire wall at a high level on both sides. I just went through these. Removed the door sills and b pillar cover, removed lining on side of cargo area - no damage. You will find it easier to do if you remove the front seat as well. It makes it easier to move the carpet and gives you full access to install the cables. I will be putting a terminal block on each cable with connections to compressor and waeco 50 in back of cruiser and then running 6B&S back to van.

The reason I went down the drivers side is because my fridge and compressor are mounted on that side, and I have 2x sets of camera cables and computer gear going down the passenger side.

Where are the computers mounted in the cruiser and how much chance is there of cooking them if the power cables are nearby.

AnswerID: 302101

Reply By: drivesafe - Monday, May 05, 2008 at 10:41

Monday, May 05, 2008 at 10:41
Hi again Ircon, I’m not up on the specific location of wire looms in 100 Series but in most vehicles you can usually find a path for run new cable by following the existing vehicle looms.

As for worrying about electrical interference and spikes, you may read, from time to time, that if you don’t buy this or that brand of Dual Battery Controller, you risk damaging your vehicle’s computers because you will not have the benefit of their spike and surge protection.

This is nothing more than cheap ( and in my opinion, desperate ) sales hype, no matter what make or model of vehicle you have, all automotive electronic components have their own built in protection so just run your cable where you want.

Back to your question and again, not being up on 100’s loom location, if the are no spare rubber grommets in the firewall ( quite common on most vehicles ) you can usually get through the firewall by making a small cut in the rubber boot that protects the vehicle’s looms where they pass through the firewall.

Just make that you have access to the loom inside the cab, then just follow the vehicle’s wire loom to the rear.

Another tip to save you some time and money. If you run your cable for powering your caravan, to the rear of your 100 first, you can use the Anderson plug terminals as a junction and run some 6mm auto twin from the Anderson plug terminals, via an inline fuse holder, to your power outlet for your Engel.

AnswerID: 302104

Follow Up By: Ircon - Monday, May 05, 2008 at 11:09

Monday, May 05, 2008 at 11:09
Hi drivesafe,

I hadn't considered the comments regarding the battery separation circuits as a problem.
I was more wondering about induced noise if I run the cables, which can carry 20 to 30 amps at times, parallel and in close proximity to the cars wiring which may or may not be carrying sensitive electronic signals.


PS I would like to start a new thread about battery to battery boosters to get your thoughts on that subject. Probably do that later.
FollowupID: 568139

Follow Up By: Shane (QLD) - Monday, May 05, 2008 at 13:02

Monday, May 05, 2008 at 13:02
I would tend to disagree with running cables wherever. I put a UHF in my VE SS & when I transmit the whole of my background of my centre LED display lights up brilliant red. At least it's a cheap SWR meter. Had the same setup & aerial in a BF Falcon & had no trouble. I would probably say reason is that the aerial I used is a 4.5 db on glass type as used in unmarked vehicles, & the radiation is too close to the display. Surprisingly Ford has similar LCD setup in a similar place, but no doubt better shielded.
FollowupID: 568150

Follow Up By: Member - Glenn D (NSW) - Monday, May 05, 2008 at 16:11

Monday, May 05, 2008 at 16:11
Hows it going Ircon,

Any sensitive wiring , data cable , shound be of the shielded type so as to prevent intereferance from outside sources.

Mutual induction is nomally associated with AC installations where the elctro magnetic field around the wire is constantly changing.

I reckon you would be ok to run power lines next to computer wiring in you car.

FollowupID: 568190

Follow Up By: Ircon - Monday, May 05, 2008 at 16:43

Monday, May 05, 2008 at 16:43
Thanks Glen,

The rubber grommet seem to be the most likely place so I think I might try there.


FollowupID: 568196

Reply By: Member - JohnR (Vic)&Kath - Monday, May 05, 2008 at 10:50

Monday, May 05, 2008 at 10:50
Rosscoe, there are two plastic grommets each side under the carpet in front of the rear seats under the carpet that are good for access and entry. You would need to run the cables through split tubing to protect them or at least the positive, if they are separate cables. You would be best advised to silicone those after running cables though.

For the front of the cabin I have come in through the front grommet.

I actually ran 32mm sq cables to the back for the Karavan charging to get plenty of amps there. I think I could weld off them if I upgraded the fuse.

I see that another contributer has mentioned the groove you can run cables through inside the car, and that is another option if you already have the cables inside, just make sure they cannot rub and short.Mine is an 06 build
AnswerID: 302107

Reply By: MEMBER - Darian (SA) - Monday, May 05, 2008 at 13:18

Monday, May 05, 2008 at 13:18
My 04 TD GXL was already wired for a rear fridge from the aux - one job saved.
Re the van charging via an Anderson at rear. I ran my cables from the aux, inside some 19mm irrigation poly, along the higher edges of the chassis, right to the back left hand corner, then round to the hitch area - the latter 500mm roughly being in the split, ribbed black conduit - with a dust cover on the 50A Anderson, I just tuck it behind the hitch when not in use. BTW - I did do a parallel cable off this power line, into the rear left of the cargo area - there is a fairly big grommet on the left rear underside below the jack that allows access up into that jack storage area - I then snuck that cable out under the trim moulding bottom left of the cargo area - that Anderson is used for a compressor / fridge backup etc.
Re lighter cables / antenna etc into the interior near the dash - I squeezed mine in through the large grommet front right of the firewall - near my ABS - sprayed a bit of silicon on I think to assist them sliding through.
AnswerID: 302126

Follow Up By: Member - Graham H (QLD) - Monday, May 05, 2008 at 17:18

Monday, May 05, 2008 at 17:18
Suggest you feel the wires on the AUX socket when u have your fridge running cos they certainly arent heavy enough for that.
They are only light gauge wire and all I run off mine is a light.

There is on my TD a piece out of the firewall insulation to the centre of the car from the steering column. It is sort of propellor shaped and right in the centre there is a spot of weld where a pin is mounted on the inside. If you drill a hole on the left hand side as u look from the front it is an ideal place to run wires into the cab. Its easy to get at and with a rubber grommet in it is easy to waterproof.
I ran my heavy wires along the top of the r/hand chassis rail as there is a wire loom there already and just cable tied onto it. If U split your batteries this is the side your auxilaries are on anyway.

If you want to put a wire inside at tha back there is a big rubber plug in the bottom of the mudguard roll at the rear which you can feed a wire up into the pockets in the side.
FollowupID: 568206

Follow Up By: MEMBER - Darian (SA) - Monday, May 05, 2008 at 19:35

Monday, May 05, 2008 at 19:35
I don't use the accessory socket for the fridge - the socket I refer to is another circuit installed for an Engel by the previous owner - comes from the auxiliary battery - there would be voltage drop of some substance in that line, but I only use it while mobile - I swap to my heavier power feed, when stationary.
FollowupID: 568240

Reply By: mangoes08 - Monday, May 05, 2008 at 18:29

Monday, May 05, 2008 at 18:29
Any of these options are OK. Just make sure a Circuit Breaker is installed as close to the battery take-off's point as possible, to protect against any future cable shorts.
AnswerID: 302167

Reply By: Richard W (NSW) - Monday, May 05, 2008 at 18:33

Monday, May 05, 2008 at 18:33
I ran the Pirhana isolator cable from the main battery to a 100amp circuit breaker then through the grommett on the passenger side to the isolator mounted under the passenger seat to a 100A/H AGM battery in the rear for the fridge etc. Then ran heavy duty cable through a 30amp fuse to an anderson plug for the trailer battery.
AnswerID: 302168

Reply By: Bonz (Vic) - Monday, May 05, 2008 at 21:22

Monday, May 05, 2008 at 21:22
Theres a rubber grommet on the passenger side up high(ish) on the firewall that you can slit with a knife and run thru, silicone it up when you're thru
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AnswerID: 302223

Reply By: Von Helga - Tuesday, May 06, 2008 at 09:34

Tuesday, May 06, 2008 at 09:34
For Rosscoe and John,

All that I have read in this forum and others suggest (read demand) 6 B&S cable minimum from front to rear for Aux power setups. Why did you use the 2 B&S? and not the same cable throughout?
AnswerID: 302286

Follow Up By: jdbb - Tuesday, May 06, 2008 at 10:33

Tuesday, May 06, 2008 at 10:33
I ran 3B&S - 32mm2 - through the cruiser to minimise voltage drop. The terminal blocks in the back of the cruiser will then feed my waeco and arb compressor, and a 6B&S cable will run back into the van via a 50A Anderson plug.
FollowupID: 568338

Reply By: Von Helga - Tuesday, May 06, 2008 at 11:21

Tuesday, May 06, 2008 at 11:21
I am a bleep .
I wrongly assumed smaller numbers in the cable designation meant smaller cable size.
AnswerID: 302297

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