guy88

Hi all, new to the site and have a strange question to ask

I am in the process of fitting a pair of alternators from a 4ltr jeep to a Transit van to provide extra power

Now my problem is, iv fitted the alternators and got the belt on, etc but cant get them to charge, on the alternators theres the big connection for the charge out, but theres 2 smaller ones and a black box with an earth cable

Iv connected both the smaller ones to charge lights but it wont light up the lights

can anyone tell me what the 2 small terminals are and what the black box is for?

need to get these to work as the bracket has been made to take them

freegdr

may be they are triggerd by 12v to energize alt spend the 20 bucks and by the manual foe the year vechicle the cam from and look at the wiring diag then sell the book on here

Bustedback

You're going to have to wire up an external voltage regulator for each alternator, and supply voltage to the field circuit in order for the alternators to have any output.

guy88

i take it the black box is the voltage reg?

I still have these just need to know what wire has to go where, got a green, greem/red and a thick black

guy88

anyone got any info on these, got a manual and it isnt mentioned in there

where can i get a wiring diagram for them?

ol"blue

You should be able to look it up in here. Jeep Wiring diagrams
And Welcome to CF.

ET JEEP

The black box is just a cable support. It holds the large B+ cable, the ground cable and the 2 field wires. The 2 small wires are the field wires. The voltage regulator is in the PCM. The PCM uses the field wire to control the charging.

The back of the alternator should have a large terminal for the B+ cable. The ground cable connects to the alternator case and the 2 small wires attach to 2 studs located close to the ground cable attachment.

There is a way to add external voltage regulators. For the 2 alternator installation that is the way you may have to go. I haven't seem too much on dual alternators on auto engines.

guy88

is it right then that i have put 12v to the field terminals and the warning lights havent come on?

ET JEEP

Here are a couple of thread on adding an external regulator. These are for a Dodge truck but it will be the same.

One

Two

The voltage regulator provides a measured voltage depending on the state of the electrical system. The field wires have no connection to the warning lights. The warning lights are wired separately if they are not controlled by the PCM. Best to use a voltmeter to measure the status of the charging system.

5-90

I'm assuming that you're dealing with the ND alternator from the 1991-up Jeep (the XJ used four different styles of alternator - the Paris-Rhone was peculiar to the Renault turbo Diesel, then the Delco 12SI from 1984 to 1986, the Delco CS130 from 1987-1990, and the ND small frame 1991-2001.) Information is key...

From your description, I'm guessing it's the ND - this may be verified by a stylised "ND" cast into the rear cover at the centre boss.

The ND has three "live" terminals on the back - the large B+ output terminal and two field coil terminals. The B+ has a black surround, and the field terminals share a grey surround. The field coils are fed by a voltage regulator, and are given a feed of (typically) 0.5-4.0VDC. More will damage things - and not just in your alternator! - so don't think about wiring the field to take the full system 12VDC!

Any external regulator will serve to energise the field coils. Many people use 1970's Chrysler regulator units, and my buddy offers Prestolite marine regulators (adjustable and not) for sale. Given a choice, I'll take the Prestolite marine units - they're tougher (no, that's not just opinion. I've seen Prestolites go four or five times as long as the typical automotive voltage regulator...)

Another option would be to have a pair of Delco CS130s reconfigured as "one-wire" units (any competent shop can do this for you,) and drop them in, thereby eliminating the wiring confusion. You can probably fit them in with minimal to no modification, you don't have to worry about wiring up the regulator (since it's internal,) and the Delco unit is more reliable than the ND anyhow.

The "black box" on the OEM subharness for the NDs is simply a moulded rubber block to locate all of the wiring terminii - there are no electronics in it. You can convert to use loose wires at your convenience with no ill effects - just make sure that, like all wiring, it's tied back out of the way of moving bits.