Alternator Wiring Question
 

I replaced the alternator in my 1983 SC, but it does not charge. Then I did what I should have done first and trolled the archives here at Pelican Parts.

Ultimately what I am asking is which wires should go where on the alternator that I just put into the car, but I will report the results of my testing as well.

When I turn the key on, the Alternator Warning Light does not light up. I do get voltage there, on both sides of the bulb, and grounding that exiting blue wire DOES cause the bulb to light. Also, grounding the blue wire at the alternator causes the bulb to light. I even made sure that I got good continuity between the positive battery cable and the thick red wire to the alternator.

I have not put anything back together yet, I wanted to post a picture of the alternator to verify the connectors. Thanks in advance for any advice on my alternator wiring or general charging issues. On the left side, 3- is stamped in the red circle and on the right side, 3+ is stamped in the blue circle. It's a rebuilt Paris Rhone.

http://forums.pelicanparts.com/uploa...1299114558.jpg

Rob
1983 911SC

Negative is the ground wires including the one to the case. 5mm
Positive is the red heavy 6mm
Blue is the top 5mm
Bruce

Does this help?
http://forums.pelicanparts.com/uploa...1299120729.jpg

My understanding would be that in this picture:<BR>http://forums.pelicanparts.com/uploa...1299121862.jpg

The #1 post at the top of the picture should be connected to the blue wire that comes from the warning light on the dashboard.

The #2 post on the lower left should be connected to the ground wires, one of which goes straight to the top of the engine.

The #3 post on the lower right should be the thick red power from the battery.

Is this correct?

Rob
1983 SC

Bump. I could really use some help here.

The only thing that I have not checked, and will do it tonight, is the transmission ground strap.

The light on the instrument panel does not light when the key is on, but grounding it to either of the grounding wires that will connect to the alternator *does* make it light (there seem to be two ground wires; one goes straight to the top of the engine and the other is a part of the wiring bundle that includes the blue wire and the thick red wire from the battery).

Also, I do have continuity on the blue wire between the instrument light and the end that connects to the alternator, though I have not taken voltage on that wire at the alternator end. I did have 12V at the other end of that blue wire just past the bulb.

Any ideas would be GREATLY appreciated. I really need to get this car running this weekend; this is basic transportation for me at the present time.

Funny, I work on my old Isuzu Trooper as well and when I decided to replace this conveniently-located alternator, I thought to myself "this is the first repair that will actually be easier on the 911 than the truck". Proven wrong...

Rob
1983 911SC

Rob,
Double check this, but it appears to me that your description of where wires 1,2 & 3 go, does not match this example. Are blue and ground reversed?

regards,

Al

Al - I noticed the apparent contradiction between your posting and Bruce's...

Bruce wrote:
Which matches the way the wires were connected to my OLD alternator.

However, yours does look to have blue and ground switched. I am at a loss though I do think that your alternator is another brand...?

The new alternator itself is not clearly labeled like the old one, nor does the one page of paper that came with it shed any light at all on the connections.

Thanks a lot for the replies.

Rob

Take a look at this post, which lists the terminals on the new style alternator:

http://forums.pelicanparts.com/porsche-911-technical-forum/84382-converting-new-stile-alternator-help.html

Though I am feeling stupid about this, I want to make sure that I document my resolution.

If you look closely at the pictures above, you can see a connector that comes off of the connector that takes the thick red cable from the battery. It's on the lower right in my new alternator pictures, with the yellow wire. Though it seems obvious now, that tab connector and the yellow wire connected to it are not positioned in a way that is compatible with the fan housing - it was crushing that connector and not only grounding to to the alternator body but the connector got partially broken.

I cut the yellow wire, put a new connector on it, and bent the metal tab connector up and to the side so that it would be out of the way of the housing.

Everything works like a champ now.

Thanks to all of you for your help on this.

Rob's looks backwards. Rob, assuming it runs that way?

Here is my 81SC with 82 alternator (internal reg)


http://forums.pelicanparts.com/uploa...1300463099.jpg

The battery light comes on when I turn the key on and goes out when the engine is running, plus I have put a couple hundred miles on it and the battery is fully charged, so I have to assume that the wiring is correct. My alternator must just be different than yours; when running I am getting more than 13.5 volts at the battery, about 12.5 with the engine off.

Thanks again very much for the feedback. I have another one that I am about to post related to a stutter of the engine...

Oops - I meant Al's picture. Not yours, Rob. Glad yours is doing well.

Howdy all,

I had my alternator wires chewed up by rats, long story about where the car was. Does anyone know where the ground wires (brown wires) connect to, there's a thick one and a thinner one, where do they go to?

http://forums.pelicanparts.com/uploa...1672518093.jpg

NaijaBerry,
Helps to post year and model…
Looks like an 84-89 Carrera engine harness so…
Thin Brown ground goes to fan/blower. Thick Brown goes to case ground.