Is this a problem?

Ooops. sorry about the empty post.

Yes. Absolutely. The other wire that you seem to be missing is for the "field coil" of the alternator. Without a field in the stator, you can spin that armature all day long and get no induced current..

Here's a simple test: Start the car and carefully reach down to the body of the alternator with a thin steel screwdriver or hacksaw blade. You should be able to feel the magnetic field of the field coil attract the metal to the case.

If you can dig up a loose connector that looks like it fits the spade lug of the alternator, give it a go...

-Fred W

I've looked. Called a Saab dealership in Atlanta & they said this particular model only has 2 wires to it. Odd that everything else I read says it should have 3... what does that wire run to? ~GJ~

...and see symptoms just like he's seeing, yup. Needs to find the other end of that wire. I'm sure whoever he'd take the car to for a new alternator would be happy to replace the perfectly good alternator with another perfectly good one, and hook up the wire, and say nothing about it being just a wire all along.

Never thought of doing it that way, but no reason it wouldn't work. Yup, if you don't supply voltage to the stationary coils, it won't set up the magnetic field, and you'll never get anything out of it. Makes perfect sense based on what he's explaining too.

Any guesses on the wire color, and/or the harness it'll be coming from? but yeah, it's the loose one right near there that fits on that connector.

Dave Hinz

Maybe your alternator has a permanent magnet. The technology has improved amazingly in recent years, allowing (among other things) motors of amusing compactness. Excitation coils become history.

Moreover ISTR that some alternators generate their own excitation current from power they produce, via an in-built rectifier. All that's needed to start the process is the residual magnetism from the last time it ran; then the alternator "boots" itself, feeding power back to build a field until everything's at full strength.

-- Andrew Stephenson

Failed...

I wish. If the wire exists, it's completely gone. I'm going to have a fresh go at looking for it today, but I combed it yesterday and no luck. I'll have to resolve this wire issue before I break the alternator loose. Where should the other end of this wire go? And would it be green/white like earlier models? This alternator does indeed have the connector on the alternator, so I would assume it would be required.

~GJ~

Yes. Try the screwdriver test, does it have a magnetic field when the car is off (would indicate permanent magnet alternator, which would be _very_ surprising)? Or, does it have a magnetic field when the car is turning it (would indicate self-exciting alternator, which would be _somewhat_ surprising), or does it have no attractive force at all (which I expect you to find)?

Sure seems like it. I don't have the diagram for that car; maybe someone else here has one & can take a look?

Bob sent me a scanned diagram that only shows 2 wires. The tech at a Saab dealership in Atl says this model should have only 2 wires, and the car did run fine for a few weeks before all this started (I've only had the car less than a month). Close inspection shows no dangling or hidden wire. I pretty much have no choice but to assume it should only have the 2. I would like to do the magnet test though, shame I have the alternator bolts out... ~GJ~

You should have at least two wires: one to regulate the electric field within which the rotor spins, one to output to the battery, a heavy wire. Ground would be through the case.

But did you not already verify that the alt is putting out 14 volts when running? And yet allows the battery to run down? I'd hook up a VOM and drive it around , see what's happening.

When started, the alt had the same low reading as the battery and declined steadily, until the engine died. I read the signal on the battery connection the back of the alt.

~GJ~