I'm about to install my 3rd alternator in the last 6,000 miles. The prior two have both failed electrically (not due to bearing or pulley problems). First replacement (carquest rebuild) worked great for about 4,000 miles, then developed pulsating voltage that made lights flicker. Second one (100% new from 'rareElectrical') worked great for 2,000 miles and then just gradually stopped putting out power.

I'm well aware that crappy rebuilds are very common, so I know the alternator itself could be to blame. But is there anything else can I look for that might be slowly frying alternators?

Belt is new and tensioned properly.
Battery is only a year old and tests good.
Battery holds charge fine - no parasitic loss.
I'm not driving through any giant mud puddles.
It's all stock - never added any lights/stereo/security/etc.

I know everyone says 'check battery cables'...but other than obvious breaks or major corrosion I don't really know what I'm looking for.

This is the only thing I saw that looked a little suspicious...Is that how it's supposed to look? Just looks odd to me that there's so much exposed wire at that clip. Is that little bit of green fuzz enough to cause a problem?





Thanks

I can tell you that my Gen 2 looks exactly the same minus the green "stuff" on the wires

I used to have an issue with the main power cable that was 'expanded' from the oxidation before it was replaced (thanks GrassCat). <img src="/forums/images/graemlins/lol.gif" alt="" /> <img src="/forums/images/graemlins/kewl.gif" alt="" />

Check the condition of the fat wire from the alt to the battery and all it's connections. IIRC, it goes thru a fusible link. Also check the conditions of all the other alternator connections. I bet a bad sense wire will cause your kind of problems.

I forgot to mention that my battery warning light on the dash never came on, even when I was running at 10 volts. Pretty sure the bulb is ok...will check when I get home. Wonder if that could also suggest a bad sense wire? Thanks for giving me some hints to go on!

I'm stuck. The dashboard battery light won't illuminate when I turn the key to ON. I pulled and tested the light bulb itself, and it works. I even tried swapping it with another good bulb and still nothing! What the heck does that mean <img src="/forums/images/graemlins/confused.gif" alt="" />

I'm not great at reading wiring diagrams...but it seems like the dash light (charge indicator) is sort of the basic starting point of this circuit and that other than a bad fuse (which I checked), there's not much that could stop it from lighting up when key is ON. Any ideas? Am I right to focus on getting the dash light to work before moving on to something else?

that diagram doesn't look like what I remember. Source? I'd use the one from the fsm...

Found that diagram online somewhere. The 1998 FSM on mitsubishilinks seems to be missing the whole circuit diagram section at the end. But I compared this to the 96 FSM and it seems accurate, just drawn differently.

Last night I tested the 2 little wires that plug into the back of the alternator.

The yellow was fine - it's getting full, unswitched battery voltage at all times.

The switched white wire gets voltage when key is turned to ON, but it's 1 volt less than battery voltage. I tested at the connector and then further up the wire with same results.

With the dash bulb not working, it looks like white wire can only be getting power through the 'generator relay'. So I'll check that out. Is it possible for a relay to go partially bad and cause a voltage drop like this without breaking the connection entirely?

Sometimes the battery will hold some charge and will test OK-But never fully charges-This will cause premature Alt fsilure. I had this happen in my TDI- Was told battery was fine but when I tried to completely charge it to put it back in car it would not completely charge.

The squiggles in the "generator relay" look like a diode and a resistor to me, which would explain the voltage drop on that wire. I don't see any control voltage for a relay coil in the box...