Alternator wiring help needed

[keithdixon]

I am changing alternator and need some help with the wiring of the new one

The new one is a "a127 65" (Pic "NEW 1")

the old was a valco va182 (Pic "OLD 1")

i have 4 cables in the loom,
1 Fat feed
black 12v which is wired directly to 12+
brown and cream (both are within the engine wiring loom

also so that i do not fry the alternator how can i test the wires to make sure they are correctly wired.

rgs

keith dixon

[Range Rover Blues]

Can't really tell from the pictures but generally you only need one thick wire and one thin wire to get an alternator working.  The thin one creates the field as the engine starts up untill the alternator is generating enough voltage to 'self exite'.
The others are for things like the rev counter and perhaps a charging relay?

[muddyweb]

Keith,

What vehicle is it ?

If you have 4 wires in the loom, the wiring diagram ought to be looked at.

Where do the 4 loom wires go at the moment ?

[keithdixon]

it's a range rover 3.5l v8 vogue

the 4 wires seem to go to

12+
fat feed
dash warning light
and tacho

but i need to know where on the alternator to fit them

rgs

keith dixon

[muddyweb]

OK...

If you have a terminal labelled 'W'... this would normally be the tacho.

The large Bolt (I think labelled B, or B+) is the main charge feed

The dash warning would be to the 'IND' terminal.

[keithdixon]

Tim,
thank you so far for your help

I have enclosed another image, this time a bit clearer.

So we have

B+
W
Empty connection

B+, easy one fat feed
w, tacho
Empty connection???

I have 2 remainding wires, one dash warning light and
a thin 12v+ supply (but i have to say that the 12v+ supply does seem to have been added at some time to the engine wiring)

i would assume that the empty connection would be warning light.

Would the alternator need an additional 12v+ supply??

We're getting there.

keith dixon

[muddyweb]

Hello,

The dash warning light is the most likley candidate for the spare terminal.  (As I say, it would normally be labelled 'IND')

I must be honest and say that I'm not sure why there would have been a need for a 12V feed to the alternator.

[nzrover]

The extra 12v wire is most likely a remote voltage sensing wire - either to sense actual battery voltage in a dual-battery system with a blocking diosde, or because there has been a historical problem with the vehicle undercharging it's battery.

[keithdixon]

OK, so ...

I'll try without the extra 12v+

but with dash warning connected to capacitor to the spare?

Rgs

Keith Dixon

[nzrover]

Capacitor would normally go to B+

[keithdixon]

there are 2 capacitors on the alternator, one plugs in next to the B+ the other will only reach warning light output peg (see pic- shown as empty connection)


rgs

keith dixon

[keithdixon]

Just a quick thanks to all who assisted.

Alternator in and appears to be working 100%

Thanks


Keith Dixon