Automotive Wiring

[K8MHZ]

Thankfully, I haven't had to deal with many issues on cars. And on that newer farm machinery with up to 1 1/2" thick harnesses, if a harness goes bad we usually just replace it.

Yes, without wiring diagrams you can end up going in circles.
Trailer wiring is usually pretty a standard color coding. I've learned the hard way that white is usually negative or "ground".

There is almost a standard for trailers!

Here is what I use. Note that nothing is mentioned about the trailer brakes needing a larger wire?

View attachment 10393

 

[delectric123]

Nice! Where'd you get that from?

 

[mgookin]

If you're up to spending $70 check this out: http://standards.sae.org/j1128_201310/

 

[K8MHZ]

Nice! Where'd you get that from?

From Yahoo images. Yahoo is my friend.

 

[K8MHZ]

If you're up to spending $70 check this out: http://standards.sae.org/j1128_201310/

I'm pretty sure that J1128 just deals with the construction and durability of the conductors and the insulation. That being said, J1128 conductors have at least passed the SAE certs as opposed to generic that may not have.

 

[K8MHZ]

This is a great site with great info.

http://www.kayjayco.com/catPWireSelect.htm

When in doubt, use 125?C rated TXL, GXL, SXL, or SGX wire insulation for engine compartment and general wiring. The only difference between these is the thickness of the insulation and cost, with the thicker being the more expensive. They are all insulated with crosslinked polyethylene, which is almost as heat resistant as teflon, but cheaper and much tougher.
For more detail, see wire tables and amps vs wire size.