Wiring Harness/Fuse Box Solutions
 

I'm converting over to a spec boxster and as I've pulled components . . . front and rear lids, seats & airbag sensor . . . soon radio/AC and convertible top.What have you done with with wiring? I've read people have relocated the fuse box from the drivers foot well.

Obviously I'm not pulling the whole car apart for the cage/chassis work where it might be simpler to reinstall a harness. I can feel some Obsessive Compulsive disorder kicking in as look at the dead ends. Has anyone remounted the fuse box? Would it be an exercise in frustration to eliminate now unnecessary wiring and could I get some real weight reduction from this?

Post pictures if you've got them.

Thanks.

As of right now, I have done harnesses for eight spec Boxsters with two or three in line. Figure 12 hours minimum to just to strip, de-pin and re-wrap everything leaving locations the same. This is best case, knowing exactly what you are doing and do it all at once. This also assumes the harness it is out of the car. I usually do two or three at a time. My "model" for that is a 996 Cup car, so that would be leaving the factory light switch and lights, as well as column switches. Figure 20+ if you are going to relocate the fusebox, get rid of column switches, relocate alarm box, add Cool Suit, aftermarket dash and sensors, cutoff switch, etc.

As far a weight reduction goes, conservatively figure 10lbs, but perhaps as much as 15+ depending upon what options the car had and if you keep lights, fans and if you relocate the fuse box and switches. The big advantage in my opinion is the simplification of the harness, leading to a much more safe and reliable system.

Steve

IMHO, make the immobilizer box top priority for moving. If it is not moved, it typically rattles around next to the driver's seat where it is subject to rain and/or physical damage and is generally in the way.

It is much easier to work on wiring BEFORE the cage goes in. Do it now if you are going to do it. You may also need to remove some of the harness to install the cage. On my car, which I bought used, the shop cut the entire harness branch just behind the driver's seat and spliced it all back together. I assume this was cage related as it doesn't look like they pulled the rest of the harness.

Again IMHO, if you want the bigger weight loss you will need to pull the dash as a lot of the heavy gauge wires are up under the dash. This winter, I pulled 30+ wires that ran to the immobilizer. It felt good to get a big bag of wire, but it only added up to 4 lbs as most of them were small gauge. I didn't have time to pull the dash, so all the wires I removed were only from the fuse panel back.

The best thing to do is to remove the entire harness before you put in the cage and work on it out of the car. It is MUCH easier to put in the cage without the harness, and much easier to work on the harness as well. Put the harness back in after the cage is in and painted. That makes everyone's job easier. Fab guys don't have to worry about melting the harness with welding, the painter will have almost nothing to mask and when it goes back together it is very straightforward. Installing a harness is no big deal. Working on a car working around a cage sucks, so do everything that you can out of the car!

When I do a harness, the only wires I cut are ones that go through the molded bulkhead grommets that will be removed. The only other exception is if components are moved and wires need to be shortened or lengthened. EVERYTHING comes apart. It is tedious, but the end result is what I think would have come out of Porsche Motorsport.

Thanks, those details are very helpful . . . now to find a DIY on wiring harness removal.

It is pretty self explanatory. Strip everything out of the car. Disconnect harness, pull it out...

I haven't removed a wiring harness before. If I was doing it, I'd mark every connector and take lots of pics to help me put things back together. Might not need the info, but doesn't hurt to have it just in case.

I'm bringing this thread back from the dead, as I'll be starting to strip my car down soon in preparation for the cage install. I'm a DIY'er when it comes to most bolt-on and maintenance-type stuff, but splicing/soldering/relays/fuses etc is all new to me. I'd like to get it right the first time though, so I'm planning on simplifying the wiring as much as possible. Does anyone have any advice on what tools and supplies I'll need to get to work on the wiring harness? Remember, I have basically no knowledge or experience with electrical stuff, so layman's terms please!

I have a Bentley manual en route, so that's a start!

Thanks

I'm no pro and am trying to figure this out myself. Hopefully Qmulus will correct me if I'm wrong about any of this, but here's my advice.
With the car stripped, the harness does come out relatively easily. Start at the ends disconnecting everything and work your way to the major bundles. In a stripped car, all the terminals and connectors will fit through the firewalls. Gradual push and pull, nothing should need to be stressed.
I am going to be modifying a harness as I do an engine swap. Here are a couple videos that I think are good info.

I like the process in this one, but I think that his crimping (tool and connector) are the weak points.
<iframe width="560" height="315" src="https://www.youtube.com/embed/yvS3D2TOucs?rel=0" frameborder="0" allowfullscreen></iframe>

This video looks like good advice on crimping and soldering. I like his tools and proceedure:
<iframe width="560" height="315" src="https://www.youtube.com/embed/H0i3CAELaC8?rel=0" frameborder="0" allowfullscreen></iframe>

For a crimp connector, my guess is that these are a good choice:
http://986forum.com/forums/uploads02...1481554307.jpg

I did my spec boxster with an absolute minimum of wiring left. I removed the light switch, ignition switch, stalks, fuse box, relay holders etc. I kept full beam lights, single speed wiper only. Mil spec high amp toggle switches replaced the porsche switchgear. I used aftermarket fused distribution panels that weigh a quarter of what the Porsche fusebox weighs. All the large connectors that were no longer populated, i replaced with smaller ones to save a few oz. The harness is now very simple, and troubleshooting is a piece of cake.

My advice is buy the proper de-pinning tools and take your time. remove the pins and the entire wire rather than cutting. You can remove 95% of the unneeded wiring quite easily. The last 5% can be a little tricky. Dont be afraid to plug the harness back in and test that the car still starts.

One exception to the wire cut will be the W line going from the alarm box to the DME. Cut this and extend the wire to allow relocation of the alarm box to up under the dash.