bad alternator luck.... need advice
09-06-13, 04:36 PM
#1
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bad alternator luck.... need advice
ok so my car is finally at the stage of at least running.... I am running a s4 na chassis harness and a s4 t2 engine harness. which means no alternator plugs, I'm running a s5 alternator, from what I have read you need a constant 12v and the cable to the fuse box. first alternator did nothing no voltage output at all, than tried a s5 alt off my parts car. charged at 15+ immediately stopped use of that one and bought a new reman s5.... now this one stays at 12v at idle and than 14.8-15.8 when revved an stays there after that....
from what I understand the other wire is just the signal to the dumy light and is not needed....? is this true? any suggestions appreciated this problem is the only thing keepin the car of the road, I'd like to enjoy it for the month or 2 I have left till winter........
from what I understand the other wire is just the signal to the dumy light and is not needed....? is this true? any suggestions appreciated this problem is the only thing keepin the car of the road, I'd like to enjoy it for the month or 2 I have left till winter........
09-06-13, 05:39 PM
#2
Used/reman alternators are a crapshoot at best. Some auto stores are better sources than others. Napa is 'usually' one of the better to choose from, but a bit more pricey.
The alternator that worked after reving is doing so because the alternator self excites itself when reved. It should self excite itself when working properlyregardless of engine speed.
The alternator that worked after reving is doing so because the alternator self excites itself when reved. It should self excite itself when working properlyregardless of engine speed.
Last edited by satch; 09-06-13 at 05:43 PM.
09-06-13, 06:13 PM
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that's what I thought,
the constant 12v should "excite" the alternator by itself correct? (for s5) it doesn't need the 1-3v from the dummy to work correctly right?
this whole situation isn't exciting me too much... ha ha
the constant 12v should "excite" the alternator by itself correct? (for s5) it doesn't need the 1-3v from the dummy to work correctly right?
this whole situation isn't exciting me too much... ha ha
09-06-13, 06:26 PM
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The 1 to 3 volt wire you speak of only has that amount of voltage w/the key to on and engine off or when the alternator is failing, otherwise it has 12 volts backfed by the Alternator Warning Light Relay. Whether it needs that voltage is a bit confusing as I have read two differing sides. W/the engine idling I guess you could run a 12 volt wire to the L terminal to see if it makes a beans difference.
Last edited by satch; 09-06-13 at 06:28 PM.
09-08-13, 09:10 AM
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so as I found out that second wire does matter... if anyone does a na to t2 swap using t2 harness do as you should run wires n repin the alt to factory na pins.as soon as I plugged the L it went from 12v on start up to 14.5 and didn't spike anymore going into 15v+
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