I am trying to figure out where the small blue wire from the alternator connects to the fuse box.

Also, should this wire have 12v when the ignition is on?

I thought my alternator was broken because it was not charging the battery, but when autozone tested it, they said it works fine, so I'm looking elsewhere.

Engine is an 86 951. Thanks in advance.

 

I'm no guru but the schematics I have show it going through a 2-pin plug to an open junction 'B39' wherever that is but it shows it near the battery? I can scan the page for you if that helps. Drop me a PM and I'll send it. My car is apart so I can't do a trace right now.

 

Steve,

The blue wire goes to a white plastic connector that has two wires come in one side by the fuse box just in front of the fire wall, the other wire is coming from the starter. I think that is the B39 connector you see. From there, the wire goes to the fuse box, and I'm having trouble figuring out where. The wiring diagram (as I read it, shows it going to a relay (G1 off the top of my head) but that doesn't seem right with where the wire goes up into the bottom of the fuse box.

Sorry if I wasn't clear, and thanks for your help.

 

bump

 

That blue wire is to "energize" the alternator's field - then the alternator can make it's own current.

The blue wire is connected to the bulb on the dash which is likely out...

Put your key in the ignition, turn it to on so all the idiot lights light up. Is the alternator light on? Probably not - if not, replace the bulb and your problem will be fixed.

 

Van,

You are right on the money. I had the same problem in my VW Bus. Alternator wiring/excitation is set up the same way. Those reading your reply will benefit. For those unfamiliar, many hours can be spent wondering.

 

Something to test to see if its a problem with the blue "exciter" wire is to start the car and rev it past 3000 rpms, these alternators will self excite at 3k.

Mark