Hello all,

In building standalone harnesses I know many (or most?) people combine a lot of the pink wires into a single fuse, thus limiting the number of fuses in the fusebox. I would personally prefer to keep each wire individually fused like the factory did. Other than ease of wiring and a larger fusebox, are their practical/reliable reasons not to do this? I feel like if one fuse blew on an injector, for example, it would be better to have one go out than all of them.

Opinions and insight appreciated.

Thanks,
Brandon

 

There are practical reasons. I would never combine several oem fused links into a single link and only maybe if I was increasing the gauge of wire appropriately. Each circuit having its own dedicated fused wire increases the overall current carrying capacity of the system. Combining too many circuits through the same gauge wire can cause unwanted voltage drops.

Also you are very right, partial failure > total failure. I too would prefer only part of the electrical system to fail instead of the whole.

 

The factory did not have a separate fuse for every wire. That would have been 16 fuses just for the coils and injectors. Maybe you should take a look at the old wiring first.

 

Fuses are sized by the gauge of the wire, not the size of the load. Like said above you don't want so many loads on the same wire that you risk pushing too much current down one wire. Similarly if you gang several wires into the same fuse, than you have to size the fuse for the smallest wire in the bunch. You lose capacity that way.

Somethings it makes a lot of sense to wire separately, like left and right headlights or emergency flashers vs. taillights. At some point it just becomes excessive, like fusing each coil pack separately. You might actually lose reliability there because you are adding so many connections. I'm not sure I would put each injector on a separate wire. Aside from too many wires to route I would worry about popping one fuse and not noticing it.

I knew a couple who built their own house and put every single electrical load on it's own wire and breaker. "Home run" they called it. Their fuse box was amazing. Every wall plug on a separate wire straight to the fuse box. A crack head could have made some money stripping the copper out of that house.

 

I prefer to setup the harnesses with 8 fuses which is more then enough. The factory does not have a separate fuse for each injector or coil. Usually they are broken down into banks so a right and left bank fuse for injectors and coils and a fuse for sensors for example.