| Author |  Topic  |
green96v4
V4 Mad
Canada
738 Posts |  Posted - 25 Aug 2020 : 19:42:28  
| Alternator experts, I need your help!!
Ever since getting my 20 year restoration back on the road, I've been living with a weird "quirk". The alternator charge warning light stays on when the engine is off (I can take the key out completely and it's still illuminated), which will drain the battery. Strangely it goes out when I turn the ignition on....
Work-around has been to just use a cheap battery isolator, but that's failing now and I've been left stranded a couple of times and gone all Basil Fawlty on the car!
Both the starter motor and alternator were refurbished by a "Specialist" but the starter solenoid failed on me the other day (luckily on my driveway) but that was the Basil Fawlty moment "Right...that's it, I'm going to give you a damn good thrashing!!!!"
I'm really beginning to tire of these so-called specialist, "Freds in sheds", haven't found a reliable one yet and I think this last specialist just gave everything a quick coat of paint and sent them on their way!
I've taken the alternator into a repair shop I've since found (who's also ordered me a new solenoid) and explained my problem he's saying the rotor wire is broken and is therefore not earthing (hence the warning light??) but can't find a replacement due to age (and 96's were never imported to Canada, dealing with the good old US of A is difficult at the best of times....)
Petri on Skanmobile classic has one, but is the diagnosis correct or am I chasing money into the wrong place?
Couple of other shots of the alternator apart, someone may spot something not right...
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melle
V4 Guru
United Kingdom
3833 Posts | Posted - 26 Aug 2020 : 10:40:08
| I had the same a long time ago, and I can't remember what the issue was! I think it was either a wire that wasn't connected to the right terminal, or the issue was with the voltage regulator. If you decide to replace it, you can fit a 900 one. This does away with the external voltage regulator, and doubles the amperage.
www.saabv4.com |
Edited by - melle on 26 Aug 2020 10:40:26 |  |
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green96v4
V4 Mad
Canada
738 Posts | Posted - 26 Aug 2020 : 10:50:10
| thanks Melle - I have a 900 owner in the area looking for a spare alternator to try it, my voltage regulator was brand new OEM stock from Highgate (remember them?)
and yes, hadn't thought it might be the ignition barrel | |
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green96v4
V4 Mad
Canada
738 Posts | |
melle
V4 Guru
United Kingdom
3833 Posts | Posted - 26 Aug 2020 : 12:00:50
| Yes, I think so, but it was suggested to me it's a better idea to fit the later type that looks like this on the back:
I can't remember why, 72sonett3 probably does.
This is the one in my 900, I believe my 96 has the exact same model fitted:
You need the pulley and the fan from the V4 alternator, the 900 alternator normally spins in the opposite direction.
www.saabv4.com | |
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green96v4
V4 Mad
Canada
738 Posts | Posted - 26 Aug 2020 : 12:02:43
| | thanks - as always you are The Oracle!! | |
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TTruckie
V4 Fanatic
United Kingdom
320 Posts | Posted - 26 Aug 2020 : 21:44:18
| you have to make sure the later one turn the correct way! some models don't
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melle
V4 Guru
United Kingdom
3833 Posts | Posted - 26 Aug 2020 : 21:48:29
| None turn the correct way, that's why you have to swap the fan.
www.saabv4.com | |
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stevebod
V4 Fanatic
United Kingdom
416 Posts | Posted - 27 Aug 2020 : 16:15:06
| Sounds like it could be a wiring fault.
You say you restored the car, so is there a chance the wiring is not right?
If it helps - the alternator light looks for a difference between the alternator output and the battery +12V.
Maybe you can trace the wires back to find which end is on 12v and which is earthed with the ignition off.
Also - Is the fuel gauge working in the first photo with the ignition off? That would be strange.
I can't work it out in my head exactly how it could be wrongly wired but it | |
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Derek
V4 Guru
United Kingdom
2191 Posts | Posted - 27 Aug 2020 : 20:47:49
| | There looks to be enough wire there to repair it by adding a short length. Some shrink sleeve for protection and shaped to clear everything and all should be well. Assuming that is the only fault of course. | |
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christophe
V4 Fanatic
France
227 Posts | Posted - 31 Aug 2020 : 10:38:19
| If this can be of any help, I recently got a refurbished Bosch 55a alternator from Rockauto's. The price was a little tad over 40€! You have to look for the one fitted to 1974 99s. It is a perfect fit but you have to take the end slip cover out to move it 1/4th of a turn. The corresponding regulator costs 20€ more. This setup worked perfectly for me.
Nice day to all. | |
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green96v4
V4 Mad
Canada
738 Posts | Posted - 31 Aug 2020 : 12:29:59
| Update on this:
Stevebod - I'm beginning to think the same, I now have a new alternator and have wired it up and the light is doing the exact same thing
Loom is new from Autosparks in the UK (patterned from a 75 SAAB kit that they do) however is wasn't perfect as 2 of the blue wires in behind the dash has been mixed up and caused me all kinds of problems when I first put the car back together - took me a while to find that one!!!
Your observation about the fuel gauge is correct too - does a weird thing where it reads correctly with just battery connected, but then has a mind of it's own with the ignition on (and I've tried a variety of different float mechanisms and even a different gauge I found on Tradera)
Only thing I haven't replaced is the ignition barrel
I guess I have bigger issues than a dodgy alternator.....
quote:
Originally posted by stevebod
Sounds like it could be a wiring fault.
You say you restored the car, so is there a chance the wiring is not right?
If it helps - the alternator light looks for a difference between the alternator output and the battery +12V.
Maybe you can trace the wires back to find which end is on 12v and which is earthed with the ignition off.
Also - Is the fuel gauge working in the first photo with the ignition off? That would be strange.
I can't work it out in my head exactly how it could be wrongly wired but it
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Mr Burrrrrrrrrrt
V4 Fanatic
United Kingdom
344 Posts | Posted - 01 Sep 2020 : 11:33:56
| | Could be a fuse not making proper contact or wiring to the instruments. For years my alternator light was on dimly and the fuel gauge jumped up and down until I found the culprit. Can't remember which fuse it was now though! | |
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chris steeden
V4 Fan
United Kingdom
163 Posts | Posted - 01 Sep 2020 : 17:28:50
| | Not something simple like a bad earth? | |
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green96v4
V4 Mad
Canada
738 Posts | Posted - 03 Sep 2020 : 11:28:54
| I've been over the earths pretty thoroughly (and the fuses)
I'm in the process of redrawing the 75 wiring loom (Autosparks had their patterned loom listed as a 75, not sure if there were and differences that I don't know about between 75 and 71, other than single horn and addition of heated seats/rear screen - guess I'm about to find out and to the benefit of the community we'll have another wiring diagram in glorious technicolor!)
a real head scratcher this one!!
Keep the suggestions coming...
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green96v4
V4 Mad
Canada
738 Posts | Posted - 08 Sep 2020 : 13:37:01
| So I'm still redrawing the 72-74 and the 75 wiring looms (Autosparks now list the loom as 72-74) and I'll post those once finished (I figure they'll be useful to others)
My thoughts are either a faulty ignition key module (which if anyone has a spare I'd be happy to purchase just to eliminate from the hunt) but I've also noticed this part listed and not sure what it's for (or where it even plugs in)
it's a Diode that is listed on Saabklubben's site and falls within my Chassis number range, but I don't recall it ever being on the car when I took it apart (which, to be fair, was 20 years ago) and don't have it in a parts bin of leftovers....
only shows it plugging in roughly to the steering column wiring, but not sure what its purpose is?
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Alternator help needed
