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Tue Nov 25, 2003 7:53 pm

Ok.. so the past few weeks my car hasn't been chargin my batt. so i just thouht maybe something was draining it.. now i'm starting to wonder is its the alt. when it idels the Gen. Light glows faintly and when you rev it it goes away..
what could this be?? do i have to buy a new alt.?

Wed Nov 26, 2003 12:44 am

Get out the Volt meter... check the voltage out of the alt directly ( rev it a bit so the Alt " cuts in" ( above 900 or 1000 RPM) you should read 12.75-13.95 V if it is puttin out.

Then check it at the battery, should have 12.5 not running and the above voltage if the charge from the alt is reaching the battery.

if not, look for loose wires/ connections in between

by the way, do you have a stock 3 prong with a regulator under the rear seat or a internal regulator model Alt????

Wed Nov 26, 2003 8:26 am

Yes.. 3 prong with reg. i'll check it today.. and let you know.

Wed Nov 26, 2003 10:31 am

CJM722 wrote: Yes.. 3 prong with reg. i'll check it today.. and let you know.

In that case checking it at the Alt. ( just put the black lead on the case of the alt and the red on the B+ post) will tell you if it is putting out. then if you do not get the same voltage on the battery the regulator is problaby bad.
Do you have a Bosch or more likey the Motorala Unit. If you have a small flat regulator ( Motorola/type it is "solid state") take the 2 screws loose and look at the backside of it. there is some gel substance covering the electrical guts. if it is melted and bubbly looking then the V-reg is definantly toast.
If you have a bosch. it has a squareish silver box ( different looking thatn a generator type regulator though) and I have not had much luck tinkering with them.
I have replaced the regulator with either style and not had a problem.
the other thing is you may be putting out acceptable voltage but not enough amps ( alt is getting weak)
I have had several cars that the light always faintly glowed and it never was a problem, sometimes it glowed brighter with all the lights wipers etc. on but still no trouble.
Depending on if you just get a regulator and it solves the problem or if the Alt is getting weak, I suggest replacing it with the Bosch AL-82 unit with the internal regulator and bypass the V- reg all together.

good luck!

Wed Nov 26, 2003 12:04 pm

Well it turned out the nut on the top of the B+ was loose.. thus not alowing full charging.. but batt. is reading 12.4 and i'm getting 12.8 outo f the alt. is that ok? by the way i have to bosch Reg.

Wed Nov 26, 2003 12:26 pm

12.8 is at the low end IMO... Was that revved up a bit and not at idle?

a good charge voltage would be 13.25 -13.95 but depending on the state of charge ( like if you just charged the battery or it is new...) 12.75-8 is probably ok... just check it with the lights and stuff on... if it drops below 12.5 then your really not getting a charge, kinda just breaking even, so in time the battery could go flat.

But It sounds like you'll be ok, I think I would rap in the regulator with a screwdriver handle for good luck and check the big reds in the white plastic plug in back there by the reg and also over to the battery and even at the fuse block and the headlight switch... pull them on and off a few times and a bit of WD wouldn't hurt... spin all the fuses in the fuse olock etc... just let your baby know your concerned and doing somthing... she may respond :wink:

Wed Nov 26, 2003 12:51 pm

If you do little nighttime driving you might be ok for awhile with an alt putting out 12.8 but I have always replaced anything under 13 or 13.2volts as I don't care for walking along the freeway.

Wed Nov 26, 2003 1:00 pm

I have actually seen some of the New AL-82's put out 14.25 and never drop below 13.5 ( unless all the lights and wipers, brake lights too were on at the same time.

If your only getting 12.8 I wonder what you get when you turn every thing on like a rainy night trip would be stuck in traffic... low RPMs and everything running?

If cleaning and checking the connections etc. does not raise the voltage, then I'm with Tingud, I would say start saving for an AL-82 or at least a rebuilt 3 prong and a new regulator if you want to keep it OG stock/ wiring and all....

Wed Nov 26, 2003 2:27 pm

Ya.. I've had it all on in traffic and no problems yet.. i'll save for a new one.. for sure.. i hate to be stranded.. But thanks for all the hope

Wed Nov 26, 2003 11:17 pm

Well I had a car in the shop today, a 73 with the 3 prong alt.. checked his voltage output for grins... 13.95! and it's an original Motorola/VW unit.

I also thought of one more thing you can do... get out the small nut drivers or 1/4 inch socket set and take the white plastic thing with the 3 prongs in it off and check your brushes and clean the surface of the commutator ( where the brushes ride) with a pencil eraser or very fine wet dry sandpaper...

if the brushes are really short, I may have some used out of old alts, dunno where you could get any except maybe an alt/ starter rebuild shop.

Thu Nov 27, 2003 7:42 am

Ok.. well i cleaned all connections and i also cleaned the brushes like you said and i'm getting a reading of 13.6.. thanks for all the help!

Thu Nov 27, 2003 9:57 am

HOOOOORAYY! we actually fixed one! :shock:

good, I hope it keeps it up for a while to come, if not you know what we would do! I just love it when a bit of tinkering pays off. :D

Thu Nov 27, 2003 11:55 am

Ya.. the tinkering pays off for sure!! Thanks for all he help..