Wire routing - getting wires from internal to external and vice versa

[B1tPirate]

How to get power into the cab for switch and back out for lights, compressors, etc is a constant topic and there seems to be a thousand threads on how to route the wires.

This is less of a questions and more of a post that I hope helps people. For wiring any DC item you have a positive wire and a negative wire.

Negative wire:

• It's a truck so the whole frame is a common ground which means there is a factory ground bolt near your switches and also near whatever you are wiring. You do not have to run a negative wire from your switch all the way to the accessory, you just need a ground wire at the switch and at the accessory going to one of these ground bolts.
• If you have to have a third ground (like with an AC inverter) run a cable from the battery so you can avoid a "ground loop" which will cause a fire (been there)

Positive wires:

• Don't go through any factory grommets that have something factory in them. A dealership may blame an issue on it, cut it, etc
• Jeeps have lots of drain holes, make sure you have well coated wire and use the drain holes
• There are vent holes in the back of the cab behind the seat, use those

General cable routing:

• Cover your wires with something - plastic loom from an auto parts store works or even empty flexible metal looms that commercial electricians use both work great and there are a ton of other options between
• Follow paths used by the factory when running cables along the frame to avoid having the wires cut or pinched when the suspension and chassis move
• Run one well protected primary wire into the cab and connect it to a water proof fuse box (https://www.amazon.com/WUPP-Blade-Warning-Indicator-Damp-Proof/dp/B07GBV2MHN/ref=sr_1_1_sspa) so you don't have 8 wires coming into the cab
• Use lots of fuses - shorts or too much power draw will cause fires, fuses can save you from a fire.

Many recreational boats and larger ATVs use a 12V system just like Jeeps so there are tons of inexpensive waterproof accessories, switches, lights, etc. that can be found and used.

Hope this helps someone. Questions are welcome, opinions are taken at face value. I have been doing unique wiring on trucks for years so I am only passing on what I do all the time. I just got a Gladiator Sport (named Spartacus of course) and will post examples of everything listed above as I add lights, a 1200w inverter, etc. I have learned a ton about my Gladiator on this forum so giving advice and help in the areas I know is my way of giving back.

Here is a picture of a 5000w inverter with dual deep cycle batteries that I installed in the bed of a Ram truck to show my experience is real world, not theoretical. The two batteries plus the main truck battery have to be wired in parallel to handle the inrush of a full 5000w load in case you were wondering...

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[twbranch]

I have a question, where are the vents behind the seats? I have a Sport S and there are no vents behind my seats. Just a couple of mesh storage nets. Thanks for the information.

 

[cafecito]

Don't go through any factory grommets that have something factory in them. A dealership may blame an issue on it, cut it, etc

This might be a good principle in general, but even the Mopar switch bank kit has you puncture and run cables through the passenger footwell firewall grommet.

I can understand advising strong caution when doing this, but no one should take this as a black-and-white rule.

 

[B1tPirate]

I have a question, where are the vents behind the seats? I have a Sport S and there are no vents behind my seats. Just a couple of mesh storage nets. Thanks for the information.

In a Sport you have to remove the plastic that is behind the seat to see them. The cable can be ran through the seat anchor holes or you can remove the side trim and go along under the door. If you are under the Jeep and feel the back of the cab on the passenger side you will feel the opening with a rubber flap over it. I am running a cable through mine later this week and can post pictures.

 

[LostWoods]

Grounding via chassis is typically more desirable than dedicated grounding because the chassis has so little resistance it can more or less be ignored when calculating wire gauge from run length. In other words, you can frequently get away with a smaller wire than you could had you run a full ground cable too. The danger is, like you said, in the event of a chassis ground failure, it's going to try any path to ground it can find whether that be your ham radio antenna through the radio chassis or your light bar you mounted through the metal bumper. It's a rare issue but it's why radios frequently have fuses on both power wires as protection.

Also, while you don't need to run a ground directly to your loads from the battery, power has to return to battery somehow so if you are adding any significant number of them or large draw loads like an inverter or switch panel (sPOD, Switch Pros, etc.) then you will need to upgrade your chassis grounds to larger gauge wire or run a parallel ground cable to supplement. The system is designed for the 110A Aux panel already in these so there's probably a lot of headroom but it's something to keep in mind for other vehicles.

Also if you want two easy ingress points, the nipple on the main wiring harness passenger side is an excellent point for a 6 gauge power cable that is completely water tight and the clutch opening cover driver side can be drilled out and sealed with a 3/4" hard loom if you have an automatic. Those are the two that I'm currently using in my truck.

 

[Beemer533]

Good post overall. Personally though, I would not run cabling through those vents; anything going through them will keep the flaps from sealing and possibly allow moisture or even bugs into the vehicle eventually.

I think using a drain hole in floor might be a better idea, or just making your own penetration.

 

[Beemer533]

I actually have everything torn out currently for a 60 delete and I have a bunch of wiring to do, here are pics of the vent for reference:

 

[LostWoods]

Yeah those leak mud even normally so I'd avoid anything that forces them open. When I pulled the back of my jeep apart, I had all kinds of dried cake in those things... I've only really been in that much mud a handful of times and never much more than bumper height.

 

[twbranch]

I see it now. Thanks.

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