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Alternator Plug Wiring

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Old 01-26-2012, 08:14 PM
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brnc_bstr87
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Default Alternator Plug Wiring

Ok I've tried to some research but got nowhere... What I have is a 1987 Gt 5spd. I've been having some problems with the battery not charging so I took the alternator off to have it tested. While unplugging the alternator the plug on the side (I think the rectfier plug?) was found to be melted on the plug end and the wires came right out of the plug. I went to the parts store to get new plug but I'm not sure how to splice in new one since the old wires are just loose I don't have a plug to reference. Can anyone tell me what wires are spliced into old wires??? Any help would be most appreciated!! Thanks :-)

Edit: Here's some more info on my problem... There's 3 wires, there's only one small wire so that's no bug deal. The other 2 are the same size and color. Does it matter which one gets spliced to???

Last edited by brnc_bstr87; 01-26-2012 at 08:23 PM. Reason: More info
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Old 01-26-2012, 08:39 PM
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Tony71502
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Sounds like you picked up a 3g alternator wiring plug(94+). The fox wiring harness had 2 wires if I remember correctly.... (upgraded to 3g like 4 years ago). The harness is wrong and you shouldn't try to rig it to work right.

You need to cut off your failed connection and take it to the parts store. If they can not find an exacy replacement then you need to search online for one or make it yourself..... or upgrade your alternator.
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Old 01-26-2012, 08:52 PM
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brnc_bstr87
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No it's the other plug and it has the same number and sizes of wires. See the plug came completely off the wires so I don't know which wires on the new plug splice onto the old wires (except the one small one).
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Old 01-26-2012, 09:37 PM
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Pictures please. If it is as simple as the plug wires falling out of the old connection then just someone didn't know how to install the conversion. I can upload pics of the proper wire connections tommorrow. I can't tonight.

It should have been spliced via wires unless you or the previous owner knows how to install connectors.
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Old 01-27-2012, 12:49 AM
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Frankenford93
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I would just do the 3G alternator upgrade at this point. My 2g alternator just started on fire. so if the wires to the rectifier are melted, you may be going down the same path my 93 mustang just went down. I was lucky I caught it before it set something on fire. 2G is a p.o.s.!
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Old 01-27-2012, 08:16 AM
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That's what I'm thinking I should do to but at this point I don't have the money to buy the 3g alternator :-(. The new plug was only $10 vs $70 but I should have the money within 2 months & will do it then. So correct me if I'm wrong, the 3g has only a one wire setup?
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Old 01-27-2012, 08:40 AM
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It has two connectors, actually. Disregard my second post, I was confused and thought u had a 3g connection when i wrote it.

Refer to this for pictures, wiring diagrams, and other useful information.

http://oldfuelinjection.com/?p=63
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Old 01-27-2012, 01:37 PM
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Yeah it's only a single wire to the rectifier and the same D shaped plug to the stator remains untouched and is reused. You should also add a 200 amp circuit breaker as well. If your local pick n pull has a ford taurus or 94-95 mustangs you could score a good 130 amp alternator from there.
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Old 01-27-2012, 03:40 PM
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Thanks to all for the info! @ Tony71502: Yeah I was confused there too at first lol but your site helped a lot! I got it all wired in plugged up, charged battery last on charger to have a full charge. Started up just fine, ran 2-3 min I turned off then back on. Ran for 10 - 15 min this time but wouldn't start back up. Something is not allowing the battery to charge! So far I've replaced the alternator plug, ignition module on distributor, & new positive battery cable. Any suggestions???
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Old 01-28-2012, 11:42 AM
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Okay here's an update from some research/work I've done since yesterday. I went ahead & bought a new regulator plug also. I'm contemplating taking the or/bl wires from the rectifier plug (first replaced plug) and running them to a new inline fuse & then to the positive side of the solenoid to bypass the original fuse in case it's blown. My question is this now haha, on the site that Tony so helpfully gave me :-), the 2g wiring diagram shows the 2 plugs sharing the yellow wire that comes out of the regualtor plug right before it goes into the same inline fuse that the rectifier plug uses. What do I do about the yellow wire??? I mean, I know it comes out of the other plug but since it goes into the same fuse that I'm bypassing do I need to include that to the new fuse also??? Here's a pic of the diagram. http://oldfuelinjection.com/public/a...ALT_wiring.gif

Also, what size fuse would I need for the new inline fuse

Last edited by brnc_bstr87; 01-28-2012 at 12:00 PM.
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