Alternator not charging battery - Saab 900 Bulletin Board - Saabnet.com
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Alternator not charging battery
Posted by Phil S. [Email] (more from Phil S.) on Wed, 25 Aug 2004 15:10:44
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Okay, I'm not a Saab guy -- I specialize in old Volvos, but I'm trying to help out a friend with some problems his Saab is having.
1990 900 16-valve turbo. Recently rebuilt (not by me) alternator doesn't charge the battery. B+ continuity to the battery is fine. D+ is only ~3V with the ignition on (should be within 1/2V of the battery or so), so that's the problem -- the field never excites and the alternator never knows to put out.
Current path is battery => ignition relay => amp warning lamp => diode => several connectors => D+ terminal.
Warning light comes on with the ignition, but goes off when running, even though it should be indicating a fault. Light is the correct 2W unit (different from the other warning lights) -- a wrong bulb here could cause a problem, but that's not it.
Ohming from terminal 87 on the ignition relay socket to the D+ terminal, I get ~400 ohms regardless of polarity. I'd expect to see continuity with the diode forward biased, and open with it reverse biased. The conclusion I'm coming to is that the diode is cooked.
I have NO idea where this diode is located. ???
To double-check this, I'd need to access two of the 59-pin connectors under the main fuse/relay block. How the heck do I do that!?
I appreciate any insights or thought you might have, and if anyone ever need help with a pre-'75 Volvo, just let me know.
Thx!
--Phil
posted by 209.166.71...
Posts in this Thread:
- Alternator not charging battery, Phil S., Wed, 25 Aug 2004 15:10:44 <-- Viewing This Message
- Re: Alternator not charging battery, Bill N, Fri, 27 Aug 2004 11:52:25
- Re: Alternator not charging battery, JimBlake
, Thu, 26 Aug 2004 04:49:03 - Re: Alternator not charging battery, Russell Giuliano, Wed, 25 Aug 2004 17:05:56
- Re: Alternator not charging battery, phil, Wed, 25 Aug 2004 16:13:54
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