alternator problem with GU patrol

[j-top paj]

ive got a problem with the alternator in my GU, TB45E ( 4.5 petrol )

its a brand new alternator so its got me stuffed how it could be broken so soon

basically i was on fraser island last year in january and the alternator died there and i only just managed to get to the barge and get off the island, back to hervey bay to try and get it fixed.

the alternator died because there was a buildup of crap in there so it was obvious why it had finally given up.. ( the previous 2 alternators had the same, mud, sand, water, and other crap etc..)

so in hervey bay at the auto sparky shop, they tried to get me a new one because they didnt want to rebuild the one i had..

after 4 days stuck there because the first one that got sent up was the wrong one, and the second didnt fit because the terminal was in the wrong spot and fouled on the intake manifold, and the third got lost somewhere between brisbane and hervey bay
they finally decided to rebuild my current one with spare parts to get me going again and send the new one to my home when it finally arrives there.


the rebuilt one lasted from mid january up until late november/early december and it needed to be replaced with the "spare" ( the new one sent down ) one.

so i replaced it and thought i wouldnt have to worry about it for quite a while as its brand new

early february the new one decides it doesnt want to charge anymore but also not light up the battery light on the dash
i only realized because the sterio started cutting out and i was wondering whats wrong so i checked the battery and found out the alternator wasnt charging.

its brand new practically, not a spot on it and has been in the car for maybe 1000ks or 2000ks at most.. just trips to the shops and back etc..


ive checked all the fuses etc.. and they are all good, ive also checked the battery light on the dash and its fine so im not sure what else to check.


there is certainly no power coming out the back of the alternator as its the same voltage as the battery and stays the same with the engine running.




anyone had similar problems? or anything else to check?


what are the two other wires coming out of the alternator?

[-Scott-]

How many wires total? If it's three, I would guess they are:

Charge wire (heavy duty wire to battery).
Sense wire - senses battery voltage without the voltage drop over the charge wire.
Charge light - this "kick starts" the exciter field, and should go out when everything is working properly.

The above presumes you have an internal regulator.

If your charge light globe is OK, but doesn't illuminate with ignition on, that's an indication that something isn't right.

If it was simply no charge light, there would normally be enough "residual magnetism" for the alternator to start charging at higher revs.

If this doesn't happen, that suggests to me that your regulator is stuffed. I've never replaced one myself, buy I understand it's a simple job.

The chimp knows a bit about this stuff - wait for him to show up.

[j-top paj]

thanks Scott, its certainly the internal regulator type alternator as when i first had to replace one the gave me the " is it internal/external regulator... oh internal, thats expensive, that will be $1200 thanks "


ive found that the higher the revs the more current draw and the battery dies quicker not charge. i tried that at first when on fraser but it didnt work
the next day i managed to drive 2hrs on the inland tracks to get over to kingfisher on a half charged battery by only keeping the revs to less than 3krpm

the battery light ( charge ) doesnt light up at all when the reds are on and before starting the car so thats my first indication that something is wrong.. but i have hardly driven the car in the last few months and the missus has driven it so she wouldnt notice something like that.

any idea on the voltage on the "charge wire" ? to excite the field winding?
id like to do some more testing before pulling it out


theres 4 wires in total;

the main charge wire with the heavy gauge cable going to the battery ( about 300mm away via a fuse i guess)
the two wires through the plug
and an earth wire to the alternator housing

[its aford not a nissan]

in regards to the plug , one should have a constant 12 volts as it is reading the battery voltage and the other should get 12 volts with the ignition on and nothing with it off

[j-top paj]

in regards to the plug , one should have a constant 12 volts as it is reading the battery voltage and the other should get 12 volts with the ignition on and nothing with it off

going in or going out?

[raptorthumper]

j-top, if your charge light doesn't come on then that's your problem. The globe is a 2watt or 3watt globe that provides a small initial current to generate a magnetic field for the windings. Globe blown = no charge. Pull the dash out and test.

I have a TB45 like you and replaced the alternator with a cheap VT V6 commodore alternator as these are plentiful and cheap as chips.

_

[its aford not a nissan]

in regards to the plug , one should have a constant 12 volts as it is reading the battery voltage and the other should get 12 volts with the ignition on and nothing with it off

going in or going out?

reading from the plug that goes into the alt

[j-top paj]

j-top, if your charge light doesn't come on then that's your problem. The globe is a 2watt or 3watt globe that provides a small initial current to generate a magnetic field for the windings. Globe blown = no charge. Pull the dash out and test.

globes are all fine, i pulled the dash out and checked them all.

I have a TB45 like you and replaced the alternator with a cheap VT V6 commodore alternator as these are plentiful and cheap as chips.

_

did it fit easy? how many Amps is it?

i guess you had to change the pulley at least?

[PBBIZ2]

Have you got the sense and dash lights back to front? I have recently gone thru this situation when changing my alternator over. No dash light and no alternator output, just battery volts at the alternator terminal.

Swap them around and it should work. This is assuming the plug has been played with and changed. When this happens its likely the globe in the dash gets blown, but if yours is ok, as mine was, it was instant success.

Do you have voltage at the dash light?

I am guessing your alternator has the solid state regulator inside - looks like a pile of heatsink fins? If it is damaged, yes, expensive to replace as they are not repairable, unlike the simple bosch regs.

Hope this is the problem. Alternately, check the integrety of the sense and light wires to make sure they have not been crushed or broken. The dash light wire is very small diameter and easily damaged.

[j-top paj]

Have you got the sense and dash lights back to front?

AFAIK they are correct. when i got the alternator in hervey bay, the auto sparkie wired the plug and it was fine for months with the other alternator. all i did when i changed the alternator was unplug it and plug it back into the new one.

is it likely to damage something if i switch them back to front?
il try it if it wont damage anything

[PBBIZ2]

If the original wiring was working, and has not changed since the sparky put it in and you changed the other alternator over, then this is not the problem. The worst you can do is blow the dash globe as far as I know.

I don't know what the connection plug is like on the GU. My new alternator has single plugs for the dash light and sense wire, hence the mix up is easy. If yours is a 'polar or horizontal and vertical pin orientated plug', you can't screw this up.

Are you sure the cable is un-damaged to the sense light? If not, this has me beat. Sorry.

[j-top paj]

I have a TB45 like you and replaced the alternator with a cheap VT V6 commodore alternator as these are plentiful and cheap as chips.

_

whats the model number?

i went to my local spare parts place and it looked completely different to mine