I got a Fit Ex yesterday, and I'm ready to start working on it. When I get a new car, I like to add a separate fuse panel up under the driver's feet and extra 12v outlets here and there. I also want to put my XM Onyx radio in there somewhere.

Any advice will be greatly appreciated.

 

Congrats on the new car! I enjoy reading about all the mods people do, so I'm looking forward to seeing all of your additions.

One idea for USB/12V placement that I saw once, that I thought was pretty neat was on the back side of the center console for backseat passenger use. Since there are already a set of those inside the console, I wonder how difficult it would be to add another set or if it'd even be possible?

I also like the idea of an additional USB port to the left of the driver, on the panel under the Econ button.

 

When I add them, I run them of an always-on fuse block. It's more convenient than having to have the Accessory position active.

 

When I add electrical devices to a vehicle I always run wires straight from the battery with a fuse right next to the positive terminal. This eliminates any accusation that my "modification" caused any issue with the rest of the electrical system.

 

Right. That's the best way. So, what I want to know is how to get the wire through the firewall. On my previous car, I went through hole for the hood release cable. I've had this less than 24 hrs, so I haven't examined it very carefully.

 

the easiest way to get wiring between teh battery and in-cabin, is to take a screwdriver, preferrably phillips, and jam it into a grommet from the engine bay into the cabin. Inspect the potential area on both sides FIRST, to make sure you will not cut or damage any wiring. Then, when the screwdriver is still in the hole, take a needlenose pliers, pushthe screwdriver out, from cabin into engine bay. you will now have pliers filling the hole. Open the pliers to stretch the hole, have an assistant put your new power wire from the engine bay into the pliers, clamp down, and pull teh wiring into the cabin


This method keeps the water-tight seal over the wiring, and is the same method I have been using during car stereo installs for over a decade.

For bonus points, have a plastic or rubber wireloom over the wire before you pull it through, so you can make it appear factory!

 

Better yet, take a smooth, rounded, tapered punch and carefully work it through the grommet. Jamming a screwdriver through can tear the insulation of the existing wires which will cause mysterious and unexpected problems either right away or down the road. Not fun with hundreds of wires in a modern harness!

 

you skipped over where I said to inspect both sides of the grommet to verify nothing bad will happen

 

Easier said than done with all the wire wrapping! Slow and careful is less exciting than jamming, but it gives the opportunity to stop and retreat if something doesn't feel right. A smooth tool is less likely to cut insulation than a ridged Phillips point.

A friend who does high-quality 2-way radio installations uses a tool made from long thin needle-nose pliers. The end is ground off smooth and after he works it though the grommet he can pull the handles apart to expand the hole. He works the wires through the gap and then pulls the pliers out allowing the grommet to collapse back onto the harness.

 

Clever. I haven't examined the firewall in detail yet.