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Discussion Starter · #1 ·
Hey guys, I haven't been to the forum in a while(forgot my old user name, back to rookie status :) ) and I have been having serious Saab issues in the last year that I just can't figure out. Basically I have burnt out 4 alternators in the last year, and after checking my output voltage today I found that my current one is putting out 19-20v as opposed to the normal 14-15. I don't know why this keeps happening and I am out of ideas. I have a 1995 900se convertible and besides the alternator I get dim dashboard lights, oddly dim headlights, one headlight motor broken, no passenger power seat(probably unrelated), power mirrors not working and currently no heated rear window(broken connection). I am thinking of putting an external regulator on my alternator this time as I seem to be burning out all of my regulators somehow, but this is only a temporary fix most likely. Has anyone experienced anything like this? Any help appreciated...
Thanks guys,
Nate
 

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The most obvious answer is a bad ground or power connection somewhere, that would also account for the dim lights, you would be dropping some voltage over the bad connection.

Less obvious, but still possible is a short, which loads the regulator so much while driving that it overheats and fails. A blown fuse might give you a hint, especially for one of the failed accessories. What would happen is this - an accessory fails and shorts. A short puts an excessive load on the regulator, until the regulator fails. The unregulated voltage overheats the next thing, like the window heater - and that fails...

( The high voltage is what you would get if the rectifier bridge in the alternator works (that is what gives you DC voltage), and at the same time, the regulator is toast. )

The main power and ground cables to the battery would have to be ok (or you could not start the car).

The secondary, smaller cables which lead to the maxi fuse box near the battery, and on from there, is where you would have to look for bad connections.

The way to find it, would be to measure the voltage first at the maxi fuse box connection, then at the battery, then directly at the alternator (not as hard as it seems, just between the lug and an engine part), and compare.

The failed accessories is where you would look for a short (measure current through the individual fuses).

4 alternators is hard to believe though, whatever the reason... :eek: :confused:
 

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Discussion Starter · #3 ·
Good advice, I will have to check out some currents after work. Yeah four of them is pretty hard to believe, but on the positive side I am very efficient at changing out an alternator now. Took me about 6 hours the first time and I believe I did the last one in about 55 minutes :)
 

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These 4 alternators, please give the source, or was just the regulator/brush set changed - which is what I do..

Many "rebuilt" major components I do not trust - a cleaning and fresh paint and a quickie test do not comprise a real rebuild..

The charging system is no better than its battery, yours is being toasted with excessive volts, is probably shot by now.
And how does the voltage sensitive ECU survive ?
Do the electric tests as PMI has suggested..
Run a resistance test on the $90 heavy red cable between the alternator, starter, and the battery...
Lay the hand on the starter to assure that it is not in a short circuit; if so, it would feel strangely hot..
PMI is on to something - the solution - something is really loading the alternator, the heavy red cable , given the chance, can do this..
 

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Discussion Starter · #5 ·
Thanks guys, I should also note that the car seems to discharge its battery at night. For example, I was able to start my car this morning but when I come to a stop for a while the CEL comes on as well as my ABS light telling me that the system is very low on power. I have to rev and use my clutch as a brake in order to prevent stalling at the light or in traffic;oops: . After I drive on the highway for a little while this seems to go away though. This is odd to me considering that I measure my idle voltage at 19v two days ago, I should keep that voltmeter with me to see if anything has changed...
 

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Discussion Starter · #6 ·
Oh yeah, the replacement alternators were purchased as rebuilt from bumper to bumper auto. Most likely just a brush/regulator swap and a paint job.
 
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