240sx Alternator Kill Switch

Does anyone know which wire on a 240sx alternator needs to be broken to properly wire the kill switch. The instructions for the switch (Moroso 4 wire) indicate an 'F' Field terminal to be run through the switch, however this may be integral to the alternator since it has an internal voltage regulator.

Choices - 8-10ga. Black from lower post - I Believe this eventually grounds; - 8-10ga white from upper post - I believe this is output back to the battery; There are 2 wires in the connector that attaches to the top of the alternator one white (16-18ga) and a red and white 20ga.

Thanks only 4 weeks till Roebling...,
Jason.

ITA 1989 240sx.

------------------

I'll check the car this weekend to see which wire I interrupted, assuming you don't hear before I post. I do recall that to cut all the electical energy from going thru the system you have to get to a wire in the main engine fuse links box.
With the kill switch in the off position, you should have no stop lights when you put your foot on the brake. I believe (this is off the top of my head so don't hold me to it) it's the white wire coming off the alt. Where are you located?
If in Atlanta area you are welcome to look at my car.

------------------
Tristan Smith
Buffalo's Southwest Cafe
ITA Nissan 240sx #56

I used to be in Atlanta, til' 1990 but now I'm in Maryland. Started flagging in w/ Atlanta in 1988. I'll be hopefully running the whole MARRS series, so if you get to VIR I'll see you there.

It would be great to find the right wire before I start cutting. The wiring diagrams and service manual are less useful in this than they could be. The battery positive is obvious. Though there is a lot that Nissan has wired directly to the primary battery cable, I'm planning to interupt all of that with the switch.

Jason.

Depends on whether the alternator has the "F" wire. Some alternators have only one wire and they start charging when they sense engine revolutions. The field wire applies battery power to the field coils. With them not energized, the alternator won't have any more drag than the mechanical resistance caused by the bearings and aerodynamic drag caused by the rotating parts.

Best thing to do is put in two brake light switches (some cars have two) and use one to energize the field only when braking while having a switch to override said function so you can have charging when you need it.

[This message has been edited by Prince Makaha (edited January 18, 2004).]

[This message has been edited by Prince Makaha (edited January 18, 2004).]

Thanks for the suggestion. Since there is no field wire marked, I think it is probably the heavier of the two wires going to the plug on top of the alternator. Once I get it running I'll be able to see if this cuts it off.

The field wire will be the one energized only while the key is on.

The "charge" wire will always be live.

Thanks - I'll let you know after the weekend, assuming I get the electrics finished. http://Forums.ImprovedTouring.com/it/biggrin.gif

Jason.