So the problem I have is my alt isn't chargeingi have a ca18det in my 1980 ute, I'm haveing problems wiring it up correctly the owner before me had the volt reg still connected so I have dis connected that and ran the red and White wire ( the charge lamp wire) into the bottom of the Alt as well as a white power wire, the top of the alt has the White and red main power into the connector. What's happening is when I start the ute the charge lamp light stays on and the volts on the battery don't reach past 12 volts. What am I doing wrong ? Should the power into the bottom of the alt be a ign source wire ? I checked the thread about IR alt wireing but still not sure what I'm missing

If your alternator is using LS connector, both connectors should be connected.
* L terminal goes to the dash Lamp
* S terminal to Alt output wire

haha beat me too it, As above.

The alternator for the CA has 4 wires. E-B-S-L. S&L are in the plug.
Earth, self explanatory = E, is black and screwed into the back of the alternator.
The Main charge wire from the battery is on a stud (shielded stud and the original was white but thick). This is B, this goes to the battery through a fuseable link or high amp fuse (around 100amps).
The two wires in the plug are S and L.
S is the white wire which is a balance wire and should be roughly the same length as the main charge wire B and terminated on B close (if not on) the Battery. There is no need for a fuse on this wire. What this does is sense when the battery is full and stops the alternator overcharging the battery. Some people drop this wire but it is not advisable.
The last wire L is a White/Red wire which goes to the charge light.
The L wire is earthed within the alternator, so your charge light needs to be feed with 12v from another source. If that makes sense?

Depending on your idle speed sometimes you need to rev a little before the charge light will go out, but once out should stay out till you shut down.

Nice explanation. I didn't realize the length of Sense wire was important but it explains the Nissan harnesses I've seen.

Here is the 1990-1995 1200 wiring.
Some alternators have an oval shaped connector instead of Tee-shape but no matter.

I should qualify, it is the resistance that is important to match, not so much the length.
So a shorter, lighter gauge S wire is acceptable.

Well I pretty much have it wired sweet then, I have about a 4 or 5 mm wire for the S wire, and I have a standard 1200 cluster with the charge lamp on the taco and its Turing on but not off, so Im assuming I have the charge lamp has a 12v feed from the Supply for the gauges and warning lights. The only part I don't have off this is and earth wire. I can't find anywhere to put one too either ? My block is earthed tho if that makes a difference ? What style connector is the earth ? A bolt end ? I'll try state my ute and rev it tho like u said

Stock Datsun 1200 runs black earth wire directly from battery terminal to timing cover bolt.

Ground/Earth Wiring#Battery




Stock 1200 engine room harness contains Alternator black Earth wire. It has an open loop connector (C-shape connector).

In USA the S13 comes with Hitachi 80A LR180 with oval connector. It uses LS wiring, but with large Oval connector instead of T-connector.

Is it what you have? Stock wiring is not thick enough for 80A. I'd run new BAT wire to new Fusible link + new Earth/ground wire.
* BAT 10 gauge
* Fusible Link from BAT wire to + battery terminal: 14 gauge
* Earth 10 gauge
This will handle up to 100A charging.

Quote:

CHG light in cluster gauge?

Sounds like its not charging. After connecting Earth wire, start engine and measure voltage of battery. Between 13.5 and 15 volts means it is charging correctly

Here is a pic of the back of my alternator. Au delivered version
The bolt on the back is the location of the earth wire.
The black shielded one at 90 deg is the main charge wire.

Hope that helps.