How To: Rewiring the front harnesses to slam the vert - (56K die)

[Grandpa01]

I recently picked up new wheels for my convertible, and when I was installing them, I noticed something quite alarming. On the passenger side, my tire had rubbed through 3-4 wires in the harness that runs from the firewall and up along the inner fender well. In addition, the plastic harness protector had been worn through on both sides of the car, exposing but not quite cutting through the wires. Obviously I'd have to move or remove these two harness if I wanted to get my car lower. Obviously it needed to go lower:



Tools Needed:10mm/12mm socket, extensions, and ratchetNeedle Nose PliersRazorWire cuttersSoldering ironSolderElectrical tape and/or heat shrinkZip tiesElectric drill and 3/8" bit

The first thing you need to do is pull the fenders off of both sides of the car. I won't go into the details of this since it's fairly intuitive. Once you get the fenders off, the harness running on both sides are very obvious. They come out of the firewall through a giant rubber boot and run up and along the upper side of the inner fender well.

Below is picture of the brace welded onto convertibles in the inner fender well to add rigidity. Upon first inspection, there seemed to be 3 options. 1. The first option is to bang the lip down at the front part of the brace and run the harness along there, tucking it under the brace. The Good: the harness won't need to be cut and there will not be fitment issues when the fender is reattached.The Bad: the harness will still be the lowest point inside the fender. So, if you want to run a large drop, you could still run into clearance issues.2. The second options is to run the harness through the hole the fender brace makes with the fender. The Good: This method provides maximum clearance and besides the time involved, is inexpensive.The Bad: This would mean cutting and resoldering every single wire in the harness.3. Drilling out the spot welds and removing the brace, thereby giving yourself near unlimited options. (I almost went this route in addition to adding a NAMS fender brace instead of the stock vert one).The Good: This method provides maximum clearance and fancy JDM (or ebay-copied) goodness.The Bad: It's the most expensive, and while rewelding the brace is possible, I would not risk it with the harness so close.



I decided on option 2. Here's how I did it.

Driverside:First thing you can do it cut the plastic cover and electrical tape off the old harness and cut off the clips that hold it up against the fender (you won't be needing these again). I used a razor for this. Once all the tape and junk is off, the harness will look like so:



***In the picture you can see Russ and I pulling out a couple of the wires not needed from the silvia conversion. You don't need to do this.

Next is the fun part. You need to cut every wire and run it through the triangle-like hole and then resolder them. I decided to do 5-6 wires at a time, cutting them at different lengths. My reasoning was that the different lengths would prevent a bulge in the harness at any one point from the solder/eletrical tape/heat shrink. In addition, there are a few instances of wires being identical colors. I did these in different phases to prevent confusion and cross-wiring, however cutting the wire different lengths also assisted in preventing any mix-ups. Getting started:



***There are two bundles of wires than run up along the firewall and into the engine compartment that plug into the brake cylinder and some other box. These wires do not have to be moved if you do not want to. When the harness is apart, you will notice that the wires run all the way up to the front of the fender and then back again into the firewall. I shortened them up since I was already in there. It's not necessary.

Here's how it looks all finished and taped up. It took a while, but I think it turned out alright. If you notice at the hole of the fender brace, I flattened the harness while taping. This helped with fender fitment.

If you look closely at the hole, I added a piece of rubber hose on the metal lip to prevent chaffing of the harness during day-to-day operation. If I could do it again, I would cut the lip there and flatten it out to allow more room for the harness.





Next I tiptied the new harness to the fender. I drilled a couple of 3/8" holes in the inner fender to run zip ties. 3/8" was simply the best size for my zipties on hand. Size will vary depending on your zip tie thickness. Here's what it looked like on the fender:



I decided I didn't like how the hood latch release cable was routed, especially in relation to the harness itself, so I pulled it out and re-routed it. It removed the latch to do it. 3 bolts:



Pop out the end of the cable with a needle nose pliers and the 3-4 plastic retaining clips, and snake it out the fender:



I ran the cable above the inner fender lip and on the outside of the harness and then through the hole to the engine compartment. Reattach it to the hood latch with your pliers and bolt it back in. If you managed to salvage the retaining clips, they do a wonderful job holding it in place, just inverted. If not, zip tie it.





Reinstall the fenders.

As far as the harness is concerned, you're all done on the driver side. There's some additional work that needs to be done on both sides to allow for an extensive drop, work that includes hammering the seem that runs parallel along the top of the inner fender well, flattening the outer fender lip, and perhaps pulling the fender if your setup so requires.

Onto the passenger side:Thankfully this side is much easier. Your fender should already be pulled. The harness should once again be obvious, exiting from a rubber boot in the firewall and running up along the bottom of the inner fender well on into the engine compartment. Remove the clips holding it in place and let it hang free. Here's where it gets interesting.

Climb into the passenger side of the car and remove the kick panel. There are 2 bolts that hold the ecu in place. Remove them and the bolt holding the harness in the ecu and set it aside. Almost directly behind the ecu is the cruise control module. Remove it, unplug the harness, and set it aside. It's the one with the relay attached to it in the picture below. Lastly is the ATC module. Unfortunately, it's a bit difficult to remove. It resides above the ecu, directly in line with the blower motor. The bottom bolt is fairly easy to get to. The top bolt is way up in the dash. You do not need to remove the blower to get to it though as it only needs to be loosened. I just fed a long thin wrench up in there and gave it a couple of twists. As seen in the picture below, the plate that holds the module is slotted at this location, so the bolt only needs to be loosened slightly. Unplug the ATC.



Cruise module:

ATC module:

At this point, the harness can, for the most part, be pulled out of the interior of the car by removing the boot at the firewall and, well, yanking. There is one final plug that goes to the ECU harness, but I found it easier to get to from outside of the car at the firewall hole. There are two final bundles running up along the firewall into the compartment. They plug into the windshield wiper motor/module; unplug them as well. The harness can now be pulled out completely.



***For those of you (like me) who have done a 5-speed swap, now is the perfect time to remove the ATC module and wiring. I used an FSM and clipped it out. I removed the cruise module as well to be relocated at a later date. Here I am removing the unneeded wires:

***

For those of you who are still running automatics, this harness is as simple as running it above the inner fender lip and back through the hole the brace makes, passing through each connector one at a time. Nothing needs to be cut. Yay!



I also rerouted the windshield wiper fluid line to clean things up a bit. Similar to the hood latch release cable, 3-4 clips hold it in place. I pulled them out carefully and reattached them inverted so the line ran above the inner fender lip.

Once the harness is passed back in the car, snug up the boot and reattach the appropriate modules and bolt them back in. Reinstall the ecu and kick panel.

This harness is now finished. Reinstall the fender.

Similar to what I noted on the driver side, there's still some sheet metal work to be done, but it's not hard if you have the right tools. Again I hammered flat the seam that runs parallel along the inner fender well, flattened the outer fender lip, and put a slight pull on the fender.

Now that you're all done, you can crank those coilover collars down another good inch or two for that slammed look:



The nice thing about doing this is the freedom you now have to adjust the ride height with utter abandon. I'd still like to drop the car another 1/4" to 1/2" all the way around, and with everything rolled, pulled, and re-routed, it'll be as simple as adjusting the coilovers.

I apologize if there are spelling mistakes or the pictures aren't detailed enough. I did my best to remember to take pictures as I went along.

Modified by Grandpa01 at 7:31 PM 1/5/2007
Modified by Grandpa01 at 2:31 PM 1/6/2007

[AZhitman]

WOW!!!

Now THAT'S how to write an article!

Perfect - It's going in AS IS!

[Eikon]

Oustanding work!!! Thanks for taking the time and energy to share that with us! Looks like it's time for you to pick out a custom title.

[onosqv]

That's an AWESOME WRITE UP!

Now I need to practice soldering, haha.

[zenkii]

cool write up...dang thats really slammed

[daconkiftador]

sorry for the threadjack, but are those the 15 or 16 sportmax 002's that youve got?

[Grandpa01]

sorry for the threadjack, but are those the 15 or 16 sportmax 002's that youve got?

They're 16x8 0 offset. I guess they just came out since I could only find 1 vendor (on ebay of course) who was selling them.

And thanks for the compliments everyone! I'll post up more how-to's as I go along, unfortunately it won't be very often for the next few months since school just started (I teach and I take night classes).

[slownslurious]

SCC did the same thing on their car but I thought I remebered them finding a way around having to cut and solder everywire...

Anyway in general its bad to lower the 240 too much esp in the front because it doesn't have a whole lot of travel, but with my 17x9 +27 in the front and my RSR race springs (very modest drop) I am already rubbing the inner fender and the harness because of my alignment... I can't figure out why nissan would have ran all that **** through the fender to start with.

[Grandpa01]

Well, it would be bad if you were not running coilovers and a fully adjustable suspension setup which would allow full travel and adjustability to allow for a proper alignment (which I am). I guess I should've made that disclaimer, but I figured anyone lowering their car this much would know this already.