2000GTV Alternator and Voltage Regulator wiring

**emulti** · #1 (**permalink**) 06-26-2006, 05:55 AM

Hello all,

been lurking too long...

I have a 74 2000GTV that was built up from a knock-down kit in Malaysia. Over the years it has had a lot of 'modifications' done to it, aircon fitted, and electronic ignition, etc.

The wiring is pretty shocking- I have been going through replacing with connectors the various twisted-wires plus tape parts in the looms, especially in the aircon wiring.

Now I am trying to sort out the alternator setup, which has been similarly tacked together. The alternator seems to have been replaced at some point, possibly not with a Bosch unit, as it doesn't look like any I have seen. At a guess, it is Japanese. The main alternator feed goes to the battery plus- that's OK.

The secondary connections to the alternator are a two-pin push on connector with very thin heatproof wires in a 'T' configuration, twisted on to two wires coming from the wiring loom.

One, the 'vertical' part of the T, goes to a green wire in the loom, with an in-line diode, wired with current flow 'out' of the alternator. The other goes straight into the loom on a brown wire.

Also on the same loom are 3 thick wires that are red, brown and black, respectively. They feed a 3-terminal box that is probably the voltage regulator, a black-painted can with screw terminals, but no other markings.

Can anyone shed some light on how this should be hooked up? Do I need the diode? (looking at the wiring it could go to the alternator light on the dash). Where does the other one go?

Hoping someone can shed some light so I can clean up the wiring in a reliable manner.

best,

Chris

**papajam** · #2 (**permalink**) 06-26-2006, 05:04 PM

I guess the first question is does the charging system (and the indicator light on the dash) work properly? Second question is are the red, brown and black wires hooked up to anything at the alternator end?

I've not seen a diode in a charging light circuit before so I don't know what to make of it.

And welcome to the BB!

**emulti** · #3 (**permalink**) 06-26-2006, 09:06 PM

The area is very cramped due to the aircon compressor and piping, and the loom disappears under the battery box. I guess I will have to pull it out to find out where the other end goes.

The charge light did come on with the engine stopped, and go out when it runs.

The strange thing is, the 3 wires to the 'voltage regulator' don't seem to go to the alternator at all. Looking at typical regulator schematics on the web, one is likely to be ground, another +12V, and the third the rotor/field coil. Of the 2 small connections to the alternator, one (green) goes via the diode into the loom, and the other brown one straight into the loom. One must be the field coil, the other the warning light. At the dash end the warning light is a green wire, so I am guessing that is the one with the diode in. (?)

Somewhere there must be a join between the output of the voltage regulator and the field coil (brown?).

I have been trying to identify the alternator without success- a pic is attached. There is no easy access from below and the aircon system makes it a non-trivial job to take it out for inspection. Anyone recognise this type of alternator? If I can ID it maybe I can find the correct wiring schematic and remove the awful twisted-wires mess.

Chris

**Tifosi** · #4 (**permalink**) 06-26-2006, 10:14 PM

Can't really tell due to the stuff in the way, but it 'almost' looks like a Ford 65amp circa late 70's-early 80's.

**emulti** · #5 (**permalink**) 06-27-2006, 12:22 AM

poking around with a mirror and torch reveals it still has part of a label on it- the model number bit is missing but it has

----------achi,Ltd Japan

Hitachi?

and a diagram of the T-connector

Crossbar/horizontal is 'S'
Post/vertical is 'L'

Guess I will have to take it out to get a better look?

Chris

**Tifosi** · #6 (**permalink**) 06-27-2006, 12:33 AM

Can't hurt other than the lost time, but the exchange for that would be the knowledge of exactly what you're working with

**emulti** · #7 (**permalink**) 06-27-2006, 05:37 AM

A little progress:

It's a Hitachi alternator with internal regulator, as shown by the designations 'S' and 'L' for Sense and Lamp.

I found some info on a site for 240/280Z owners with photos that match my unit. http://www.atlanticz.ca/zclub/techti...wap/index.html

The diode is mentioned here too- on Z cars, when an internal-regulated alternator is fitted, it's fitted in series with the lamp wire to stop the engine continuing to run when the key is turned off. Apparently the alternator can power the ingintion through the charge lamp when the key is off and the engine running.

I can't see how this can be a problem on the GTV though- for starters, the diode is the wrong way round. current flow should be only into the alternator to start it charging, after which the internal wires take over.

The 'voltage regulator' box remains a mystery, since its cables go back into the loom that runs across the front of the car to the fusebox. They are not on the wiring diagram (thick red and brown, thinner black). I will have to trace the wires. I don't think this VR box (if that is what it is) actually does anything with an internal regulated alternator, but I want to be sure before I pull it.

The Nissan site implies the sense wire ought to go direct to the battery positive, and not into the loom- to compensate for the volt drop along the main charging cable. Presumably, though, it could also go to the fusebox and keep the voltage up to 14V there? Which is best?

This car has also has a Bosch electronic ignition with Hall effect sensor in the distributor, but the wiring to that looks stock.

Chris