Alternator wires help

Posted by RayBan GST, Jun 29, 2012
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  1. RayBan GST

    RayBan GST Proven Member

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    hi all,

    i have searched but cant seem to find my problem , yesterday i was on the high way and i saw the battery light on my dash , it kept on going on and off telling me that there is something wrong in charging.

    i jacked the car and locked under and i found that this wire on the picture is loose and was almost out , i am very sure that its the dummy light for the oil !!!

    here is a picture of what i mean its not my picture its just to show you which wire was loose ( THE YELLOW COLOR) i removed it and put a better and way THICKER wire and fix it righ back and tight it and now the light of the battery is no longer present and all back to normal , the question is what does this wire have to do with the alternator ? i tracked it down and its really connected to the alternator here is another pic of an alternator and the yellow color wire connects to the three wire on the alternator pic the 2 orange and the one black .

    can someone explain please and if i did something wrong ? i dont want to blow something up by putting thicker wire i have no reall knowledge when it comes to electronics.
    thanks
     

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  2. luv2rallye

    luv2rallye DSM Wiseman

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    That yellow wire in the first picture IS for the dummy oil light. It must ONLY go to the dash oil light - NEVER to the alt!

    In your 2nd picture the 2 large wires on the alt you call orange, actually are white but have been discolored with age. The other alt wires aren't shown in your picture but if you have the stock alt, they should go to the alt 4 pin connector (shown here: http://www.dsmtuners.com/forums/attachment.php?attachmentid=68187&d=1159354383) and are red, black-yellow (sometimes this is blue), green, white.

    You can always replace any wire with a thicker one - just don't ever increase a fuse size (blow amperage) unless you REALLY know what you are doing. All wires in a car are designed (thick enough) to only handle the stock fuse size - increasing the fuse size can melt wires and start a fire.
     
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  3. RayBan GST

    RayBan GST Proven Member

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    hello there,

    i think i have different alternator , my car is from Japan and all the wires for the alternator looks different

    have a look please at this pic , the place where i put the circle , this is where i track the wire that i put on the dummy oil light :confused::confused:

    does it really make sense ???
     

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  4. luv2rallye

    luv2rallye DSM Wiseman

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    Your alt certainly looks different alright. But I can't believe it connects to those alt wires because when the oil light sensor closes (eg. key on but engine not running so oil light goes on), it would connect the alt to ground - a complete short. Does your oil light go on when key is on but engine not running?
    You need to unwrap that harness tape/casing to see what that wire really connects to. I suspect it's just another wire using the harness as a means to protect it and get closer to the area the wires go through the firewall. You might look at where those big alt wires come out near the engine fusebox to see if there's another wire in that harness.
     
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  5. pauleyman

    pauleyman DSM Wiseman

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    That wire may appear to go there but I doubt it. It's just in the same loom. What you're likely seeing is a failing voltage regulator and it's worse when the car is hot. Put a voltmeter on the car (DVM temporarily connected will do) and watch it. If the voltage starts to die out to 12v and you get a battery light the alt is starting to crash. Crash completely and one of two things happens. Car will run off the battery until it craps out and nothing works. Alternator will overcharge and stuff starts to burn out and melt. If you lights ever get real bright or you notice your power windows or wipers etc work really fast shut it down and tow it home.
     
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  6. RayBan GST

    RayBan GST Proven Member

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    the oil light goes on when the key is on but not engine running , and if i remove this wire that i connect to the oil dummy i will immediately have a BATTERY light on the dash board . so for sure it has something to do with the alternator hence i have the battery light , i can not track it now its 48 degrees now with 80% humidity so in the night i will try to take more pics for you and track everything down

    now when the ac is on ( two fans are on) and lights are on , and windows are closed if i ever touch the power window to try to close it more once its already closed i will have a real drop in RPM and you can feel it that the car is dying to 0.400 RPM once i remove my hand from the power window it goes back to 0.700 or so

    same thing will happen if i try to put high beam , once i turn the high beam i will have real drop also in RPM.

    what shall i do ? i am really white when it comes to electronics :)
     
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  7. luv2rallye

    luv2rallye DSM Wiseman

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    Without seeing wiring diagrams of your Japanese made car it's hard to know what's going on (although I'd probably have to know Japenese then). If you have the wire removed while engine is running does the battery light come on?
    You're going to have to follow that wire in the harness and see what it connects to.

    As far as trying to close the window more when it's already closed, it's normal to have a small RPM drop with engine at idle when you have other devices also drawing power (ac, fans, lights). The window motor is always supplied with current as long as you operate the switch and when the window is closed the motor draws more current when it's armature is not rotating but voltage is still applied. So the more current takes more engine power to run the alt which must supply current to everything. It should not drop anywhere near as much when engine is above idle however (>2k) or alt is bad.

    High beams at idle can do the same thing.

    The stock 2g's in the USA have a different oem alt (with 4 wire plug) which senses higher loads (current output) and sends a signal to the ECU to speed up the idle (via IAC motor).
     
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  8. RayBan GST

    RayBan GST Proven Member

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    thanks for the answers , i will try to get you some pictures of what is exactly happening and will report back soon
     
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  9. RatFink1096

    RatFink1096 Proven Member

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    Help! Cant find 100% varifiable anwser. I have a 95 awd tsi with a 6 bolt swap. Now the alternator needs to be replaced butvthey put a 1g alt in there, so i got a 2g pig tail for alternator but dont know which wires go where? Colors dont match up i got a big red one, a big white one, then a green and a black i believe heres the best anwser i got but idk if its correct or not
     

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  10. speedster39

    speedster39 Probationary Member

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    Test the alternator by unplugging the battery negative cable while the engine is running. If the car dies then it's a bad alternator. If the car engine is still running while the negative cable is disconnected then it's not the alternator and might be a low charge or bad battery. It happened to my car. My car would sputter and jump back and forth like when you try to step on the gas pedal and let go while it's in gears. The battery and check engine light would come on while this was happening. The alternator was getting worse and worse as the week gone by with the above symptoms worsened until it finally gave up and died.
     
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  11. RatFink1096

    RatFink1096 Proven Member

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    I took the alternator out and replaced it with a 98 galant 90 amp one. I rewired the pigtail so it was back to 2g plug using the diagram i posted above but am getting light surges at high rpm, so i would like to confirm with someone that the diagram is right, i knowni states 1-2-3-4 for the plug position of said wire but is that if ur looking into the plug or looking at it from the wire harness side?
     
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  12. 1990TSIAWDTALON

    1990TSIAWDTALON Proven Member

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  13. 1990TSIAWDTALON

    1990TSIAWDTALON Proven Member

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    I did a screenshot for you........

    2g alternator plug picture.png 2g alternator plug picture.jpg
     
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  14. RatFink1096

    RatFink1096 Proven Member

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    I think that should work. But i had this issue and its been bugging the hell out of me, so here it goes. I bought a new battery starter and alternator about a month ago, but last week i noticed when i was getting on it and in high rpms (at night if that matters) and all of the dash lights and everything got SUPER bright! Scared the hell out of me cause i thought i was getting an alt spike and was going to fry everything. But never blew any fuses. So i went to autozone where i got my reman 98 gallant 90amp alt and asked em if they could check it with it on the car.( keep in mind i tested it myself with car running and was pushing like 14.3 volts) and they tell me that my battery is bad, and that the reader was saying the battery had 100% charge with 12.99 volts. And wouldnt be able to check the alternator. I kindly explain that i had the battery checked the day before i put the new alternator in to make sure it was good before i went and got a new alt. And it came back good. And that i believed the regulator in the alternator was bad and could have over charged my battery causing it to fail? What could be going on. I dont have a voltage gauge in the car so its hard for me to tell wht its doing when driving. I still notice the cel dimming everytime the Flasher goes on, even with no headlights or anything else on...it shouldnt be doing that with a 90amp alternator...what am i missing...it does has a battery relocated to the trunk so maybe the ground or something? And now today i noticed my idle dropped from 1100 where it would normally sit, to about 750 or 500 rpm. Could the battery or alt or both cause that? When i went to get it checked again today they said battery had 12.79 volts and was bad and alternator was pushing 13.7 volts. But shouldnt it not be pushing 14 volts since the battery is 12+ volts. Cause they kept defending the alternator saying its good and they always push 14 volts all the time...is this true? Cause i could of sworn thats not right
     
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  15. 1990TSIAWDTALON

    1990TSIAWDTALON Proven Member

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    I'm sorry but I used to rebuild alternators and starters. If the regulator is subpar it will allow it to over charge like you are describing. Alternators just have a regulator, rectifier bridge, diode trio and a brush set in them so they are pretty basic. I would have a different shop test it or borrow a volt meter from someone and test for over voltage issues on your own so YOU know what's going on. A lot of members don't like parts store alternators but mine is working fine...so far and its a Galant unit too.
     
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  16. RatFink1096

    RatFink1096 Proven Member

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    I checked it with a volt meter and its showing like 14.3v but i dont have a way to measure it while driving since it only seems to happen when accelerating pretty hard. Lights will get super bright for a sec then go back to normal...punch the gas again and yet again the lights get super bright then when i let off it goes back to normal. And autozone is insistant on the alternator being good....just everything else is my issue....yeah maybe now that their overcharging alt fried all my sh**.
     
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  17. 1990TSIAWDTALON

    1990TSIAWDTALON Proven Member

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    If your dash lights are doing that, find a hot wire inside the cab and check your voltage when you do a pull or whatever makes it do it. Or run 1 dedicated wire in from the battery and hook up in the cabin. Just a suggestion to help you know for sure if its going out of range when your spinning it hard.
     
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  18. josh408

    josh408 Proven Member

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    I'd say don't run an autozone alternator, I got a 90 amp one same as you from them. was bad right out of the box. the voltage wasn't consistent and a lot of other members swear up and down that oem is the way to go. I can only tell you my experience with an AZ reman'd alternator, I bought an oem galant alternator from ExtremePSI and am upgrading the alternator wiring to a 4 gauge. I can let you know how that works out but my money is on just the alternator. Autozone only does a bench test and it's usually a Bs test in my opinion (I use to work there for 3 years, not proud of it) bench test and load test are completely different.
     
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  19. RatFink1096

    RatFink1096 Proven Member

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    Thanks ill have to check it out. Talked to manager at autozone, he said its more than likely alternator over charging...or spiking. Cause now my battery is coming up bad but shows 100% charge with 12.97 volts...shouldnt autozone give me a new battery since the alternator i bought from them ruined my 1 month old battery
     
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  20. RatFink1096

    RatFink1096 Proven Member

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    Haha thanks, yeah I've had my hands full with buying sh** parts from them. Then when ya tell them theres an issue they blame you or ur car, like 90% of the time LOL. I know the alternators gobout quite often to begin with but was hoping to get lile a years use out of it first haha then tale it in to get rewired by professional reputable company
     
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