Wire s4 alt from scratch
 

Okay, I am running a standalone on my car. Originally the plug for the alternator was on the harness that sat on the engine. That's all gone. So where do I runs the two wires that are on that plug. I'v seen the diagram that shows one goes to igniton switch and the other goes to dash. So where is the ignition switch wire and where is the dash wire? I thought I had it correct but My batter has been draining. Anyone? Hailers? Aron Cake?

I am sure someone can answer this better than me, but I know for a fact that ALL alternators require a +12v switched source to "energize" the regulator, otherwise the alt will only put out +11v. So the one that goes to the ignition is probally that wire.

You are right about only one thing in this statement: Someone else can answer this better than you.:rolleyes:


To the OP: wait for the experts. I am slightly qualified. There are better guys on this that you already named, but here is my help.


S5 and S6 alts require the wire is 12v continuous voltage. Are you sure that the alt is an S4? If you hook and S5 or S6 up like an S4, the battery will drain! The bahavoir described is exactly what one would expect if an S5 or S6 alt were wired like an S4.

If the alternator is really an S4: S4 requires one switched wire. The other wire goes to the dash for the alt warning light.

Does your alt light light up when you turn the key on before you start the engine?

Did you verify that the ignition connection is switched and is 'dead' when the switch is off?

If your battery is draining, did you try switching the two wires? One is black/white the other is white/bleck on the original harness. It won't hurt anything if they are reversed, the alt just won't charge correctly.

Good Luck!

is this what you are referring to? there if you need any more explanation you can look in the fsm/wiring diagrams.

I agree, if you wire it according to that diagram your battery should charge properly.

Alternately you can take the wire that goes to the dash to a stand alone battery voltage meter which is what I did rather than the alternator warning light. That way I get a voltage output reading rather than just a warning light.