Wiring harness mod

[tmoretta]

Very disappointed in FFR's woefully inadequate assembly manual directions for adapting the WRX wiring harness to the 818S: Their schematic shows the "main fuse panel" above the fuel tank on driver's side and the other fuse panel under the dash. Well, after mounting the one panel above the fuel tank (sensible because it gives good access to the engine harness and starter), the other fuse panel (the one originally under the dash) ends up in the middle of the center tunnel. I have had to add 36 inches of wire to each of approx. 40 wires in order to be able to mount the panel under the dash. Did I make the wrong choice or was FFR remiss in their directions?

[theburner9]

I'm mounting both over the fuel tank with all the relays, computer and fuel pump controller. I figured it was easier to extend the few wires to the column and headlights than all the fuse box wires

[Goldwing]

FFR was vague, but I took it as a challenge. I guess I Forrest Gumped the fuse panel part. After laying out the harness and extending everything else where it needed to go, my fuse panel reached all the way to the nook above my pedal box. My plan is to make an access cover to reach it there. After spending over a month on the harness, I was ready to let the fuse box sit wherever it worked easiest, that nook was it. The oem harness really is a major part of the build, time-wise.

[tmoretta]

The main fuse box (under the Subaru hood) is sealed to weather so can be confidently mounted above the fuel tank. The other fuse box is meant to be mounted inside the cabin - out of weather harm. I am not confident that the fuel tank area will be sufficiently protected from water/rain. I silicone sealed my ECU before mounting it above the tank on passenger side.

[wallace18]

I have built a 818S with the VCP harness and am building one now with the OEM harness. IMO you must completely strip the OEM harness of all tape and covers. This will allow you to mount as per the manual for the most part. Both my builds used a 2002WRX and the harness is not exactly like the one in the manual. After much work it has become somewhat manageable. There is no comparison of the 2 harnesses IMO. The VCP unit is by far for the money the best option IMO. If you need an OBD port for State Inspection there are some other options out there. The OEM harness is the cheapest way to go but adds 8-12 hours to the build IMO. I will add a inspection door to the kits center console for access to the FB panel.

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[wleehendrick]

I like the fusebox location. Only 8-12 hours? I know you're fast, Tom, but I'm anticipating/dreading spending much more time than that on my harness! Craig did a great write-up on the 06 harness which will help a lot, but I'm still considering the iWire option! (I have a Cobb Accessport and want to keep the Subie ECU/OBD port)

[Goldwing]

I know! Only 8-12 hours? Add a zero for me! And a few coils of solder, and a soldering iron or two. If I would have rushed it to get 12 hours, the headlight switch would likely have turned on the dieted rear window defrost, lol.

[jharris]

Hey Guys,

I had a great call with Bob G (Bob_n_Cincy) about the Subaru wiring used in the 818. He has done some really clever and smart things with his harnessing in the first of his two cars.

We've been going through the details here. We can easily create an 818 configuration using our standard 3-Cell Kit. This would be like the setups that we have for the GTM and the '33.

Essentially, this kit would replace the body controller part of the OEM harness. Both of the OEM fuse boxes would be eliminated as would most of the wiring harness. At the end of the day, the controls in the car are pretty simple. They are just made needlessly complex because of all of the unused functionality left in the harness.

I have the guys laying out a few things now. We'll have more tomorrow.

Jay

[jharris]

Okay Guys,

Here's what we came up with. At the end of the day, this is just a software variant of our standard 3-Cell Kit. This is the same system that we've been selling to Factory Five builders since 2008. It's lineage comes from the original I Squared Engineering 1+1 and Million Mile Systems going back to 2006.

Here's what this kit can do for you. It would completely eliminate the body control part of the Subaru harness. You'd simply wire the body functions (lights, ignition power, starter solenoid, fuel pump controller, cooling fans, horn, etc.) with the 3-Cell Kit. This also gets you the advantage of being able to use any ISIS accessory product with the system. That includes our inLINK key fobs for alarm, security and immobilization, inTOUCH NET for complete smart device control through a touch screen and inRESERVE for active battery management. You can scale the car as far as you want with the our system.

The 3-Cell it gets you one MASTERCELL that connects to your switches. It also gets you two POWERCELLs, one for the front and one for the rear of the car. The POWERCELLs are the equivalent of a local fuse & relay box. They are mounted in the car where you need them, ideally close to the things you're controlling. You then run a thin data cable to let the cells talk to each other. This link will take you to a good video that shows everything that you get with the 3-Cell Kit.

This link will take you to the configuration sheet for the new 818S configuration. This defines where all of the input and output wires go in the system.

This link will take you to a good video that shows all the details on reading one of our configuration sheets.

Lastly, we worked up a quick document that goes wire by wire in the harnesses of the 3-Cell Kit to show you how you'd connect them into the switches and outputs of the 818. We know that some of the aspects of wiring can be pretty esoteric so we tried to get a good summary of what is going on. We clipped out the connector and switch details from the Subaru manual to show you where things need to connect. You can get that document at this link.

Take a look at this and let us know if you have questions.

Jay

[john g]

This is a timely thread as I have been working on my wiring for the past week. I have placed the main distribution panel over the fuel tank and the fuse panel in the center console ahead of where gear shift will go. Both are in "mock up," that is sitting in position, but not attached.

This positioning required me to extend wiring in both the front and back. For the front I have extended wires for the gas pedal, ignition switch (and related steering wheel controls), front lights, fans, and horns. For the rear, I have added wire to transmission monitoring (controls) and air pump, which I hope to keep for environmental reasons. I have not yet worked on the rear lights.

In terms of harness diet, I removed the air bag system but so far have left everything else. My plan was to get the electrical system working and then remove what is not necessary. I am so far sticking with this plan, but am tempted to eliminate some wire bundles such as the heating and cooling. The ABS system is an obvious target, but at this point I don't want to rule out activating the ABS in the future. Any suggestions are greatly appreciated.

I agree that the instruction manual is inadequate, and I would be interested in contributing to more clear instructions.


John

[GUNS]

John,

I deleted the ABS and Airbags....that's it. For me, it just wasn't worth the time and effort. It does create some unneeded bulk, but it's manageable.