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FC: alternator B+ wire

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Old Oct 25, 2012 | 11:11 PM
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FC: alternator B+ wire

Anyone know what size the B+ wire is. Just got the car 3 weeks ago and the guy told me there's a short somewhere and i think I've found it. This is how it looks like when I took off the electrical tape. The wires aren't even touching each other under that metal thing that was on there. The previous electrical tape had melted, and it had water corrosion. I do apologize if this has been covered and I've used the searched button and google but nothing comes up, and FC3SPRO's website to download the FSM is down right now.


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Old Oct 26, 2012 | 01:13 AM
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I believe I used like 6 gauge when I rewired the cables in that location.I used thicker when I fed the starter though.I relocated the battery so it is hard to explain without pics and so on.
That part you have there looks like the first section that runs from the battery Positive and goes to the alternator.
It also splits and leads off to a Black connector that would feed the one side of the Main fuse (engine bay fuse block).
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Old Oct 26, 2012 | 03:11 AM
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So this wire is not just one piece that goes from the alternator to the battery? It splits to the main fuse? I tried soldering it earlier but by soldering iron is not hot enough for this thick of a wire.
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Old Oct 26, 2012 | 06:41 AM
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ya,a soldering iron won't really do anything on this thick of a wire.
I got the eyelet shaped ends to go on the alternator and used a slightly bigger male to male connector on the Part where it splits.I got one gauge up,which allows it to slip over the cable covering while the cable is not stripped.feed the cable where you want to have the "T" then strip.Put the other piece that goes would feed the fuse into the Cable connector on one side..I bashed it with a Hammer.lol..There!.Other side had an eyelet to feed the fuse bock.
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Old Oct 26, 2012 | 06:46 AM
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Oh,In my first post I mentioned a wire that has a connector that leads to the fuse block.When you make the New wire that has a T to it,so the New wire feeds the ALT but then splits to the fuse Block,You will get rid of that little Connector.
So when you go to the Fuse block,strip the wire harness down and Find that Piece of wire and take it off the harness..it is about 16 inches long.You no longer need it.
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Old Oct 26, 2012 | 10:30 AM
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grrrr.... this is like a math problem to me hahaha.... thanks for the help... i'll try to figure out what your saying hahah.... i need a diagram, but cant find it anywhere. Well if all else fails, i'll just get a mini torch, and use that to heat up the wire... lol
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Old Oct 26, 2012 | 10:43 AM
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Originally Posted by fc3s_213
grrrr.... this is like a math problem to me hahaha.... thanks for the help... i'll try to figure out what your saying hahah.... i need a diagram, but cant find it anywhere. Well if all else fails, i'll just get a mini torch, and use that to heat up the wire... lol
It's not that hard. You have a rather short lengthed wire that runs from the positive battery terminal to the engine fuse box. You then have a wire which comes off the Main fuse in this fuse box which runs to the Ignition Switch. This wire also connects to the wire coming from the alternator. And the wire running to the Ignition Switch also splits off and goes to the interior fuse box so as to power the two circuit breaker fuses at the top of that particular fuse box.
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Old Oct 26, 2012 | 08:59 PM
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thanks satch... im gonna go to the junkyard tomorrow and try to look for one and trace the wires so i can see what you guys are saying. If i fail, idk what else im gonna do lol... probably go with the torch idea which will be my last resort.
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Old Oct 26, 2012 | 09:11 PM
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I'm no good with computers,so I compromised and took a pic of a drawing I made to explain.
here..(don't laugh!).supposed to say B+
Attached Thumbnails FC: alternator B+ wire-b-wire-005.jpg  
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Old Oct 26, 2012 | 11:42 PM
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No offense misterstyx69, but I need to do some error correction here.

The alternator output (B+) cable is 8AWG and is spliced into the fuse panel's input cable which leads to the battery's positive terminal. Mine was spliced from the factory using what appeared to be a large staple. See my build thread here for the pictures of it: https://www.rx7club.com/build-thread...tormas-888195/

After all the old electrical tape is removed and the fuse panel/alternator cables are extracted, the smart thing would be to cut the alternator cable off and replace it with some 4AWG cable. Every FC will sooner or later see an alternator upgrade to either a FD or Taurus Alternator (the most common choices), so the 4AWG cable is a pro-active move. I recommend using welding cable in the manner illustrated by Aaron Cake here: Proper RX-7 Grounding Procedures

As for the fuse panel to battery terminal cable, it simply bolts onto the main fuse with a M6x1.0 bolt. If you can find a lug that will fit the opening, replace it with new cable. If not, cut out the bad section and run it straight to the battery positive terminal. My own FC did not need any of the fuse box wiring replaced, so I just gave it a new lug after separating the alternator cable from it. If yours does need replaced, a clever idea would be to re-use the old alternator cable for the fuse box to battery cable if it is in good shape. It already has a lug crimped on that will fit the fuse box's input terminal.

Would also HIGHLY recommend using Marine Battery Terminals as well. Aaron Cake refers to these in the preceding article. Also,if you've gone to the trouble of extracting the positive cables, the negative/ground cables might as well be replaced too. See Aaron Cake's article for more info.

fc3s_213, I don't mean to harp, but did you check the Second Generation FAQ? Items such as this are mentioned in it and it would probably save some frustration on your part to bookmark it here: https://www.rx7club.com/new-member-r...faq-fc-782402/

Sgt Fox's site Foxed.ca should be listed in the FAQ too, and has the manuals/parts catalogs for nearly every rotary car ever made.
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Old Oct 27, 2012 | 07:18 PM
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thanks white comet.... i did look at those links you posted above... its just really weird because i was looking for the ground at the strut tower, and in my car its nowhere to be found.
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Old Oct 27, 2012 | 07:22 PM
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i've traced the wire from where the battery is and it just goes into the harness... and idk where it ends
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Old Oct 28, 2012 | 10:21 AM
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Extracting the battery cables is a pain in the butt to do, but surprisingly simple. Just need to start unwinding the tape on the Front Harness along the driver's side. If you're going to do it, might as well redo all the large power cables in one fell swoop. If you need to re-loom everything, visit your local hardware store's electrical department.

Locating the main ground can be annoying, especially on a darkly-colored car. It is in the location that Aaron Cake illustrated, but actually seeing it may be slightly difficult when everything is loomed together as it is from the factory. You may try looking in the driver's wheelwell at the captured nuts, specifically for a M6x1.0 one. I believe it is the 3rd one down from the top, but I could be wrong about that.

One thing I would suggest above and beyond Aaron Cake's grounding guide is to put the new bolt in from the wheelwell side, so it acts as a stud. This makes it much easier to line everything up for reassembly or later modification.
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