Wiring Loom - 12v Wires

[Roundy]

Hi All,

I am about to start making a new loom for my car, and I am just trying to figure out the best way to deal with the 12v feeds that are needed.

Is it best to run individual wires for each item? (i.e. 4 feeds for injectors), or do you run 1 or 2 larger ones and then take off them?

If it is number 2, what is the best way to take off the power from these lines?

At the moment, I have been planning to run individual lines, and have chosen my firewall connectors based on that. So I have no shortage of pins available to run multiple 12V lines.

I should note; My battery is behind the passenger seat.

Any help will be much appreciated.

Cheers
Nathan

[wa5]

is this for your ST185?

[Roundy]

It is indeed

[wa5]

silly question, whats wrong with the factory loom?

[Roundy]

Not silly at all, I'm not saying this is a sensible decision on my part.

Basically I still have a lot of wires that are now redundant that I ultimately want to get rid of, and the move to COP will add some wires, but make even more redundant.

The wiring I have at the moment is a total mess due to the method I have used to wire in the ECU, so just want to tidy it up.

[RA35GT]

Toyota just have a single wire splicing off when required.

When i did my car i did the individual wire thing with individual fuses. When i redo my car I'm doing it the toyota way lol. My loom ended up massives

[Roundy]

That was my concern, looking at like 40-50 wires or something like that.

So if it is splicing, what is the best method to do that?

[RA35GT]

Toyota used crimp splicy things similar to this http://au.element14.com/te-connectiv...rel/dp/2310125

I started using a connector with a daisy chained 12V input on one side and then took the feeds out of the other side of the connector.

[Hen]

I ran a single 12V wire for each use. For example one injector positive, which I then split off to each of the injectors. I soldered and heat shrank (shrunk? shrinked?) it where it splits off to each injector, though crimps may be more suitable. Just make the connection a bit further back from the injector than you expect, so you have a little more room to play with.

All the feeds are individually fused, so I have a fuse for injectors, one for ignitors, one for ECU, etc. I had trouble finding an elegant solution to splitting the 12V feed out to these various fuses, and currently use an industrial terminal block, but I'm sure nicer things exist.

[ToyTA22]

I ran a single 12V wire for each use. For example one injector positive, which I then split off to each of the injectors. I soldered and heat shrank (shrunk? shrinked?) it where it splits off to each injector, though crimps may be more suitable. Just make the connection a bit further back from the injector than you expect, so you have a little more room to play with.

All the feeds are individually fused, so I have a fuse for injectors, one for ignitors, one for ECU, etc. I had trouble finding an elegant solution to splitting the 12V feed out to these various fuses, and currently use an industrial terminal block, but I'm sure nicer things exist.

I'm the same as you Hen, run a single supply rail then solder and heat shrink individual wires for devices. The same with individual fuses as well per circuit.

[Roundy]

Thanks for that guys. Now another question, what sort of size wire would you recommend? Obviously none of these have a huge constant power draw, and the negative side of the looms are quite small wires really.

[big_zop]

Great idea on the daisy chain connector RA35GT.

Keep it the same if not bigger gauge than the factory. As for the actual size needed, either buy a gauge ruler or take it to match up what you need.

I have done a fair bit of 'de-wiring' of my car so maybe you could do that to yours - it involves stripping the looms or all conduit/tape, pulling out what you don't need (either cutting it out or separating it out whole and removing the wire/pins from the connectors) so that you only then keep what you will use. Would give you a better idea on how it was done by Toyota and you shouldn't need to worry about getting the right size & lengths and you would then still be able to use the wiring diagram for those bits.