battery light coming on at 2500 rpms??

ok i go for a drive tonite around the block, and i noticed when the engine revs to about 2500 rpms the battery light slowly starts illuminating. starts real dim then britens as the rpms go up. the second the rpms start to go down it goes off.

i just did a 3g swap back in november, charge indicator looks good, right in the middle, lights seem fine, etc.......i did use the stock 2g pulley on the 3g alt if that helps any.....battery is only a few months old as well but that doesnt mean much i guess.....

any ideas???

i suppose the belt could be slipping but, would the charge indicator start dipping down if that were the case??

i'll have to check it tomorrow.....as for the alt.......atleast it has a lifetime on it!!

HISSIN50 said:

I wonder about the gauge too. The switch and sense wire runs to the battery light, but I dont know if the gauge ties into this in any way.

I might grab your DMM and make sure you really arent losing volts when the battery light comes on (hook the DMM up in the interior in such a way that it stays connected and have a buddy watch it and the battery light and stock voltmeter while you drive).

Ya know, I would also check the wiring connections at the alt real quick, just to make sure they look copacetic. Did you leave the stock charge cables connected, or do it like Kevin did (IIRC, I think we turned your thread into that real long one about the different ways to wire it up) and pull that wire out of the stock harness?

I bet it is something stupid. I just originally thought belt slipping due to the revs and load relationship vs the light coming on.

Good luck.

Good luck.

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i'll throw the volt meter on it when i get a chance tomorrow.......i don;t know if i'll even need to drive it to see if it's losing volts, it will do it in neutral just revving it to 2500 rpms....i should be able to check it under the hood while it's running...

i used the 3g cable from pa performance and did not re connect the orange black wires, though they are still in the harness and connected to the selenoid....i'd left them on there because there was some confusion ( on my part) as to weather or not disconecting them would also diconnect another wire that needed to be connected....i still have the wiring diagram i'll look at it again and see exactly which wires run where........seems like to remove the black orange wiring harness you just need to re-route the stator wire to the alt.......but anyway.......i did it the semi correct way.....used the new power wire and didn't re connect the black and orange....edit--there is a yellow/white wire that ties into the black and orang wires.......down in the harness. i need to figure out what to do with that before i disconnect the black oranges from the selenoid...the stator wire i can just run from point a to b out of the harness......but that yellow/white one......?? it appears i would just run it to the power wire lug on the alt..

i'll just have to see what the volt meter says........but i did notice while it was doing it ( batt light coming on) the charge guage was well above where that batt light should come on...last time that batt light came on was when the 2g alt took a dump, and it ofcourse stayed on untill i replaced the alt.

it may have been doing this but i didn't notice it as having the t-5 you rev the engine more than say just cruising with an aod...

wht93gtEd said:

with my limited knowledge on this topic, it's for the voltage regulator I believe...


also, as far as the battery light goes; it's a shift light!

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.......thats exactly how it was acting...damn car

well i went out today and wouldn't you know it, it's not doing it.......however, last nite when i was checking the alt wires my stator ( excitor wire) seemed a tad loose. i used a spade connector meaning to get the plug and wire that in.....so perhaps that was the problem.

i had the lights on, heater on, it had about 14.7 volts at idle, when i'd snap the throttle it would jump up to like 15 something on the meter but then settle back at 14 something......i'm guessing thats normal??

anyway, no shift/battery light today

as for the alt wiring, it appears from the diagram i have the yellow/white goes to the power lug on the alt, the stator wire goes from it's point a to point b on the alt, and the other wire in that harness is a green one, which ironically is the battery warning light wire.......so i think if i run the stator and yellow/white wire to their respective places, and remove the green batt wire from the harness, i can un hook the black oranges from the selenoid and scrap the rest of the harness......i also now see the advantage or use of that plug the one poster used on his car back when i'd started that 3g post in november...but i think i can do it without that at this point......that plug just makes it cleaner.......