[AndrieK]

A while back I got my hands on a scrap dash harness out of a Dualis+2. I've been stripping strands out of this on occasion, to build new harnesses for all the electrical stuff I've added to the Patrol.

This weekend I decided to completely disassemble the thing because it's becoming a bit of a crow's nest. I separated everything out into different colours, so now it's easier to grab just the bag with the colour I want to use.

But now I have some questions... There are a few wires that are twisted together in pairs. They're not shielded or insulated separately and ran with the rest of the wires throughout the harness. Always two wires, never more.

Question is; why are these like this? What is the purpose/benefit?

If I'm building new harnesses, should I be doing the same? (It does make it easier to route them through confined spaces if they're like this.)

If I can do this, can I do more than two at a time?

 

[Haggie]

A while back I got my hands on a scrap dash harness out of a Dualis+2. I've been stripping strands out of this on occasion, to build new harnesses for all the electrical stuff I've added to the Patrol.

This weekend I decided to completely disassemble the thing because it's becoming a bit of a crow's nest. I separated everything out into different colours, so now it's easier to grab just the bag with the colour I want to use.
View attachment 521185

But now I have some questions... There are a few wires that are twisted together in pairs. They're not shielded or insulated separately and ran with the rest of the wires throughout the harness. Always two wires, never more.
View attachment 521186

Question is; why are these like this? What is the purpose/benefit?

If I'm building new harnesses, should I be doing the same? (It does make it easier to route them through confined spaces if they're like this.)

If I can do this, can I do more than two at a time?

They could be canbus wires. Twisted pair so not electrically disturbed from other (inductance) signals in the loom.

I am surprised they are not shielded if they are.

 

[AndrieK]

That's what baffles me as well. There were some 2-core shielded wire in the harness as well, which I assumed was for CAN, but these wires were definitely not shielded.

 

[Benny Jahmin]

Having been through a 2009 isuzu dmax loom from start to finish the canbus wires, abs sensor wires and speaker wires were all like this and not sheilded.
There isnt much electronic wizardry going on in a 2009 dmax so i can comment on something a little more modern.

 

[turps]

I would to start my mess again.
Pull all the wiring out. And then make a look that’s labeled and in one bundle.

Maybe I should strip a patrol for the loom. Then I would get spare factory plugs also.

I need to go through my wiring tub and sort it out. I started with it in zip lock bags. Then it turned into a mess.

Sent from my iPhone using Tapatalk

 

[AndrieK]

I seriously thought of getting a Patrol loom, but I think I've got enough wiring to do what I want to do. And a set of spare plugs would be very handy, but most of the time I'm after the mating part of the plug in the harness, so another harness isn't going to help much with that.

 

[rumcajs]

They could be canbus wires. Twisted pair so not electrically disturbed from other (inductance) signals in the loom.

I am surprised they are not shielded if they are.

They're CAN bus wires and yes that is the purpose. As current flows through a conductor it induces magnetic field so for CAN bus communications of very low voltage (0.5V-4.5V) it can induce ghost voltage or noise corrupting the signalling.
So twisted pairing cancel out magnetic field therefore ....
The automakers are a cheap lot so that's why they're not shielded.

Regards

 

[seth.jxl]

I think you might find those are speaker wires. Its common place for the speaker wires to be a twisted pair and the gauge looks a little heavy for CAN bus. Not saying it cant be CAN bus, but the fact there are two short pairs and two long pairs and they are different colours, looks like speakers to me.

 

[AndrieK]

I think you might find those are speaker wires. Its common place for the speaker wires to be a twisted pair and the gauge looks a little heavy for CAN bus. Not saying it cant be CAN bus, but the fact there are two short pairs and two long pairs and they are different colours, looks like speakers to me.

Definitely not speaker wires. I disassembled the dash harness myself and they were all over the place going to and from various spots throughout the harness. If they were speaker wires, I would expect one end of all of these to have terminated in the same connector, i.e. the one that would've plugged into the back of the audio unit. There were also more than the 4 sets in the photo.

My first thoughts were signal wires or CAN, but the fact that they're not shielded confused me. So if what @rumcajs says is correct re shielding, I tend to agree with him that they were most likely CAN.

 

[seth.jxl]

yup, you're right, speaker wires for the Dualis are not those colours. Should have checked that first. I jad a carolla that had twisted speaker wires so that was my first thought, the gauge just looks rather large for CAN, but maybe its just easier that way in manufacture.

 

[Overboard]

Twisted pair is normally signal cable for a digital system even if that digital signal is just the ons and offs measured by an ALB transducer. It doesn't need to be shielded in most situation because the interference it gets from cross talk on other circuits is some orders of magnitude lower than the signal on the circuit should be. The four twisted pairs in a normal ethernet cable are a good example of this use of twisted pair without a shield.

 

[seth.jxl]

Twisted pair is normally signal cable for a digital system even if that digital signal is just the ons and offs measured by an ALB transducer. It doesn't need to be shielded in most situation because the interference it gets from cross talk on other circuits is some orders of magnitude lower than the signal on the circuit should be. The four twisted pairs in a normal ethernet cable are a good example of this use of twisted pair without a shield.

Yup, but i think the twisting is not to sheild wires, its done to help induce interference equally in both. Once the wires end at the device (what ever it is), it can balance the signal between the two wires to turn the noise out of phase. It can be done with analog devices too, like with microphone xlr cables.

I think I'm going off topic here...sorry.

 

[AndrieK]

I think I'm going off topic here...sorry.

Nah, Mate. This is very interesting! I know just enough of this stuff to be dangerous.

I couldn't be arsed to do it but now I feel like I need to go find a wiring diagram for this harness to see if I can figure out what the twisties were for.

Job for the weekend, maybe.