Alternator wiring????

[bbarooo]

I am hoping someone else has run into this. I have a 71 Blazer that the po converted to an internally regulated alternator eliminating the regulator on the core support. The battery lead is connected to the post on the alternator and then jumpered back to one of the two plug terminals. The other wire disapears into the harness back to the firewall. I have an amp draw killing the battery that only goes away when I unplug the alternator. Any ideas??

[tim_and_bobbi_blazer]

If your alternator is a 'three wire' type with a white plug containing a white wire and a red wire and then a single, large red wire that attaches to a treaded post then this is how it's usually wired:

The red wire in white plug ties (usually looped) to threaded post to connect to the battery (the big red wire that goes on a screwed post)

The white wire in the white plug (I'm assuming it's the one you say 'disappears into the harness') will tie to the brown wire (switched ignition) that went to your orginal externial regulator.

If it's hooked up correctly, there won't be a amp draw because the brown wire is switched ignition. That is, unless you have another problem.

I would suggest you cut into the harness and see what the po did. Next, find the orginal brown wire, connect it as described above, and see if your problem goes away. If you still have a problem, let me know.

[bbarooo]

That is exactly what I needed!! I went back to it and found that the radio, which is normally powered with the ignition switch, came on as soon as I unpluged the alternator. The red wires (big and little) are exacly as you described but the second wire in the plug runs to the fuse panel and plugs into the spade terminal marked for the radio.(spliced in with the radio)
So far I am unable to locate the original brown wire but I am thinking that if I seperate the alternator and radio I may be in business. The plug on the alternator has a diode between whiteand red that may let power bleed through to the radio. Sound logical?

Thank you for your help.
Brandon

[tim_and_bobbi_blazer]

Brandon, there shouldn't be a diode in the alternater plug.

I'm assuming your talking about the same set up as an A/C compressor has. That diode is to elimanate voltage spikes from the clutch. The alternator doesn't need it. The only reason I can think of why a diode would be across the alternator plug would be for radio noise reduction but I'd think it would be a capasitor (spell).

The switched ignition (brown wire) I'm refering to SHOULD be in the plug on the engine side of the fuse box.

You actually have two harnesses coming out of that plug. One is the engine harness that has your coil, water temp, starter, etc. in it and the other side is your light harness that also has your alternator regulator wires (white, blue, red, brown) in it as well as horn (dark green) and your black/white fused wires. I don't have the print in frount of me but if you untape a little of the harness, you should be able to find the brown wire I'm talking about unless the po did away with it.

Either way, the alternator shouldn't directly connect to anything in the cab.

Let me know how it all works out.