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If the bulb is out on your battery light, the alternator WILL NOT charge at all. The battery light should come on with the key on and the exciter wire connected to the small terminal on the alternator. This may be the root of your problem. If you have 12V at the alternator, that's coming from the battery connection. Try running a wire directly to the small terminal of the alternator from BAT + and see if you get 14.3V then with the car running. Either the bulb is out or you have a problem with the power feed on the green exciter wire that runs through the bulb to the alternator.
Im going to run a wire to the small terminal of the battery now
 

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I jumped a wire from
The 12V is coming from the battery. If you still have the big cable connected on the back of the alternator and it is not charging, you are reading battery voltage, not alternator output.
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I jumped a wire from the small terminal to the battery and it still just read 12.1v at the battery. What does this mean?
 

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Did you start the car with the jumper wire connected, allternator belt on, and then check the voltage? There will only be battery voltage until the alternator is operating. If the alternator is working, the jumper wire should get it charging once the car is running. No need to disconnect the jumper wire once the car is started.
 

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Find the exciter wire on the alternator - it's the single small gauge wire. Turn the car on, don't start it, and connect that wire to ground. Does the light in the dash turn on? If yes, the bulb is fine and the alternator is the problem. If not, there is a problem with the idiot light bulb or wiring. Get a ~500ohm resistor or a small (~2w) incandescent bulb and some wire... alternator exciter terminal -> bulb OR resistor -> battery. The light bulb (if used, versus resistor) will be on. Start the car. Light bulb should go off, alternator should be charging.
 

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Did you start the car with the jumper wire connected, allternator belt on, and then check the voltage? There will only be battery voltage until the alternator is operating. If the alternator is working, the jumper wire should get it charging once the car is running. No need to disconnect the jumper wire once the car is started.
Yes i just did it again to double check. With the jumper to the small alternator terminal go positive side of battery. The multimeter shows 12.1v at the battery after running for 30 seconds no change.
 

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So
Find the exciter wire on the alternator - it's the single small gauge wire. Turn the car on, don't start it, and connect that wire to ground. Does the light in the dash turn on? If yes, the bulb is fine and the alternator is the problem. If not, there is a problem with the idiot light bulb or wiring. Get a ~500ohm resistor or a small (~2w) incandescent bulb and some wire... alternator exciter terminal -> bulb OR resistor -> battery. The light bulb (if used, versus resistor) will be on. Start the car. Light bulb should go off, alternator should be charging.
So i did what you said and the battery light illuminates. So should i go ahead and order the alternator?
 

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Yes, I would concur that something is wrong with the alternator if the battery light illuminated when you grounded the wire. The alternator connection at the small wire should be a ground when not running so something internal in the alternator is preventing that, and probably also preventing the exciter charge to be recognized to initiate the alternator into charging.
 

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FWIW, the one I just ordered (should be here today) was 100% new from DB Electrical and includes the pulley. They had outstanding product ratings and looks like they do a lot of alternators for heavy duty diesel applications. I read all the posts on here about only Bosch or having original rebuilt. The only place that rebuilds them near me wanted $120+.

Db Electrical 400-24003 Alternator Compatible with/Replacement for Saab 9-3 1998-2003, 900 9000 2.0L 2.3L 2.5L 3.0L 94 95 96 97 98

Not pushing any brand (it might be made in China, who knows) but it was $72 on Amazon, then I paid $10 more for a 5-year replacement guarantee. At least if it fails in the next 5 years, I'll get my $$ back on it. If you just bought a rebuilt Bosch a few months ago and it already failed and you're having to already buy another, that is not good. :)
 

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The hit rate on reman alternators (and starters) is quite bad as Mio suggested, but when buying these parts reman FLAPS are my go to... Because if & when there is a problem it's fast and painless to get fixed up.
 

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Seems like so. If you can scare up a light bulb or resistor and some wire I think it's worth the second check, but probably you have a bad alternator.
So to confirm for the light bulb test i simply run a wire off exciter terminal on the alternator, to the bulb and then to the battery positive terminal and the light should be illuminated, and then after starting the car it should go out IF the alternator is charging. By it staying on would signify a bad alternator.
 

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Yep.

Needs to be an incandescent bulb of about 2w ... a little more won't hurt, less may not serve the purpose.

Like so:

Slope Rectangle Line Font Parallel


In this case, we are bypassing the ignition switch... that's not good for production because we don't want the light on 24x7, but for this test it's fine.

If this DOES work, the bulb is suspect. I have definitely had cars "with bad alternators" where someone has replaced the ~2w battery bulb with a ~1w everything else bulb. A 1w bulb will probably not be enough load to start charging. If this does turn out to be your situation, a bandaid is a ~500ohm resistor in the exciter wire to provide the load and just leave the bulb for the idiot light. Plenty of cars are like this from the factory.
 
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