I'm doing a little rewire on a buddies S4 turbo. I'm stuck at one spot though. I'm working on the harness that starts at the positive battery terminal, goes to the starter and also goes down to the plugs for the reverse light switch in the back of the transmission.

Now for the part I'm stuck on. This little clump of wires at the end here off by itself (in the picture). There's 1 ringlet, if you trace this wire all the way back it goes to the Main fuse. The 2 other wires, one has the plug you see on it and one looks like it's been cut off. Does anyone have any idea where these go to? It's the last piece in the puzzle of this damn wiring harness issue. Thanks.

Dave

 

White plug looks like CAS

 

Interesting, you might be onto something. Think the round eyelet could be for the back of the alternator then.

 

also looks like the power steering pump connector,and then another connector that has been cut off for fluid level sensor?.
eyelet goes to main fuse box.
....Strictly guessing with what the pics show..

 

W/respect to the cut wire could you perhaps provide the color of the wire(s) in that segment?

 

Just to make things clear, this is part of the Engine Harness, not the Emission Harness right?

The ring terminal that is traced back to the Main Fuse is the Alternator output cable (E-03). I would just cut it off where they are spliced/stapled together and crimp a new ring terminal onto the cable going to the main fuse. Most guys upgrade their alternators anyway, so running some fresh 4awg cable from the alternator to the battery's positive terminal now would save time and headaches later. See Aaron Cake's Grounding FAQ for more information here: Proper RX-7 Grounding Procedures

The white connector could be one of two connectors: FE-04 (Front to Engine Harness) or E-08 (CAS). You can follow the wiring from one to the other as it is a straight line with the only identifier being where the shielding splits off and is routed into a ground connection near FE-04. With how close it is to the alternator terminal, I'm guessing the white connector is for the CAS.

As for the chopped tail, can you tell us the wire colors in it? My gut feeling is pointing to it being for E-02 (Alternator) based on the proximity to the output cable's terminal (E-03). If my hunch is correct, White/Black and Black/White are the colors and it will be an easy fix with a couple 0.250" Quick Disconnect female terminals in lieu of the proper Yazaki 250 series connector. If you want to use the proper connector, they can be found in the stereo wiring kits for the S4 at your local parts store. It is in the left of this picture:


Depending on your friend's plan for the alternator (stock, FD alt, Taurus one, etc), you may wish to not use the original connector. As most owners know, the S4's alternator is overworked from the start. Just adding an aftermarket stereo (headunit only) can easily push it over the edge. See my gallery for proper wiring on both FD & Taurus Alternators.

 

Thanks Akagis. Judging by what you've said they're my alternator and CAS plugs.

Now a stupid question. Electrical is not my forte. I've undertaken this project to force myself to learn it. Now for the question. I'm doing a trunk mounted battery setup. I've run the thick cable they gave me from the battery to the power cable going to the starter. Now, for this wire going from the alternator back to the positive terminal. Can I just splice this into the main positive cable I have coming from the battery where it's connected to the starter harness? Or should I run a wire from the alternator straight back to the positive terminal without splicing it into anything? Thanks.

Dave

 

The smartest thing you can do right now is extract the battery/starter cables from the Front Harness, then replace them with 4awg welding cable that are soldered together per Aaron Cake's Ground FAQ. This will give you a better understanding of how power is delivered between the battery, alternator, starter and fuse box.

For a relocated battery, the proper method is to do with a short cable (<1ft) to a circuit breaker rated at 50% above the highest load you will encounter. All manual trans starters draw ~100A when cranking the engine. Iffy cables will make the starter draw more power and will trip a 150A circuit breaker after 10 seconds of cranking.

Sonic Electronix sells breakers for cheap, so get a couple to make it worth your while. Even with shipping included, buying two from them will still be cheaper than getting one from Autozone.

From the breaker goes your long Delivery Cable to the front. With cables this large, splicing will mean nothing but headaches. The correct method is to have an underhood distribution point (not the starter). Your long Delivery Cable will run from the circuit breaker at the battery to the Front Distribution Point, then have appropriate cables to the Alternator, Starter and Main Fuse. I used a bus bar from a GM fullsize truck as shown here with a red label:


The identical unlabeled bus bar is linked to the Main Ground point and serves as an accessible point to ground any additional underhood circuits. Both bus bars also double as the appropriate jumpstart points. Since this picture was taken, the bus bar on the strut tower is now for Ground while the one mounted lower is for Power, to make reworking my Haltech Harness easier.

More details can be found in my build thread here: https://www.rx7club.com/build-thread...888195/page13/

As for mounting a battery correctly in the rear, look at how I did mine. It is very similar to Aaron Cake's design, but made to accommodate both a stock Group 35 battery and my overkill Group 48 Deka Intimidator.

 

The white plug looks like it has some shielding on it?? Would look like frayed SS braiding. I think I can see that in the pic. If that is the case it's the CAS, no doubt about it. The eyelet could be a ground though in the area?? I am unfamiliar with the stock harness. Or like someone may have mentioned, it could be a connection to the alternator. Either are in the area?? As for the other, no idea! Someone chopped it.