Electrical Where does the wite wire on my alternator go?

[ahelwig]

I have an 85 CJ7 with a 350 in it. Im trying to clean up the wiring hacks that the PO had done. I also just put in speedhut guages so I cleaned up my dash wiring as well. My alternator has a large red wire coming out of the back then on top there is a plug with a white wire with a diode and a red wire that ties into the red wire coming out of the back. Im just not sure where to run that white wire with the diode. I understand what the diode is for. I do have a loose white wire in my engine compartment and it says "XLPE (its hard to read but I think these are the letters) RESISTANCE DO NOT CUT". ANother note is it seems to be a smaller gauge than most of my wires in the engine bay and it is a solid wire (not stranded) It goes into the firewall plug and from what I can tell changes to a tan wire labeled GEN LMP that goes to my fuse block and is screwed into the GEN LMP location.
SO does the alternator white wire connect to the skinny white wire that says "do not cut"? The alternator white wire is a different type (stranded maybe 14 g) than the engine compartment (very thin solid wire).
Thanks!

 

[TSB8C]

Since you have a 350 engine, I assume you also have a GM alternator (a 10-SI or 12-SI would be quite common). That diode is to prevent feedback through the excitor inside the alternator from the ignition circuit. The alternator needs this excitor voltage to start outputting; but feedback would keep the engine running after you shut of the ignition (the battery voltage through the alternator would "feedback" through to the ignition circuit). So the cathode or negative side of the diode (end with the band on it) goes toward the alternator and the anode (end without the band) goes to a keyed ignition source. A 15 ohm 5 watt resistor or an indicator lamp works just as well. But you already have the diode. That is why you have the smaller wire going to the firewall junction block and then under the dash. You could hook this wire to a "charge" indicator light with the other side of the light connected to an ignition voltage source as well. Basically you need a small resistance (diode, light bulb filament, resistor, etc) between a switched +12V source and this terminal #1 on the alternator. Terminal #2 on the alternator is the "sense" input for the alternator to know how much voltage it is putting out. That is why you tie that line straight to the battery or the alternator's output lug on the rear (which of course ties to the battery). Here's a diagram: