Alternator charge light peculiarity/problem.

[Slim]

I'm fitting an alternator to my *cough* Morris Mini *cough* and we (actually, the friend doing the wiring) are having issues hooking up a charge light.

Normally there's a terminal to which you connect a light so it comes on when the alternator is not charging and goes off when it is charging normally. So far we can't get this to happen with any of the terminals on the back of the alternator.

At present, the light comes on when it's charging and goes off when it's not. There's 4 terminals in total and all have been tested with a multimeter, but none give the desired output.

This is a picture of the little problematic guy... Note the Toyota bolts and 1JZ turbo manifold nut.


It was sourced from another friend who said it came on a generator (ie: not from a car) and is made by Mitsubishi industrial.

Is it possible that there is no way to hook up the charge light normally on some alternators?

We are trying to avoid using a relay to reverse the signal because it's an unnecessarily messy way to do things... unless it is actually necessary.

I'm starting to think that maybe there is no provision made for charge light on this type of alternator. Seems strange though.

[ScreamingHeap]

What's the model number of the alternator, ill have a look at the pin outs for you.

[midnight_purple_GA70]

Depends if it works the same as a toyota one...

wilbo666 [licensed for non-commercial use only] / Toyota Alternators

wilbo has done a great writeup of how it all works there...

you should be able to mimmick the above setup if the mini works the same...

[Slim]

ScreamingHeap : I will see if i can find a number somewhere on the unit (when i get home). From memory, it didn't have a label or sticker like i would have expected.

midnight_purple_GA70 : That's a sweet link and good general information. But it still just shows the warning lamp hooked up in a manner that we've already tried.

[ScreamingHeap]

All good, the number may be a casting mark rather than a plate.

[The Witzl]

yeah quite possible there is no charge light output.
Fit a voltmeter instead?

[DX20VT]

Lol,

Common problem. The fault is in the car not the alternator.


If the light comes on when it is charging then it is wired properly,
but you have no ign power to the non alternator side of the warning light.

usually a blown fuse, but in that it could be bad wiring.

[WiLo]

if i remember to pick up a new battery for my multimeter ill have a look at what stock alternator does tomorrow night.

what have you done in regards to voltage regulator?
looking at the factory diagram the light is fed from the regulator on one side and the non constant 35amp fuse on the other

[river]

Hi,

It is a little fella, eh? Was the original an alternator or a generator?

seeyuzz
river

[oldcorollas]

it could also be a mitsu clone from a chinese generator, ala Mitsubishi Alternator A3T06099 Images, Photos, Gallery on Gasgoo.com

mitsu alts have been used in mazda and nissan as well.. should be easy to find a diagram

is it internally regulated?
4 pin or 3 pin plug?
any letters cast next to the plug etc etc etc.. picures of back of alt will help

[Slim]

Photos...







You can see there's the big terminal with the red cover, then there's a plug with two terminals and another single terminal by itself.

As i was looking at my own photo, i noticed the "L R" on the sticker. Would that be the same as the L and S as described in the writeup by wilbo666?

Below is a similar kind of regulator as in my alternator (it came up in google images when i googled A7TA0477A)...


For what is the P terminal?
.


Edit : Further googling came up with this image which suggest "R" is probably the same as "IG"....

[oldcorollas]

http://mgaguru.com/mgtech/electric/pics2/alt001.gif
http://www.team.net/www/rootes/sunbe...ps/altconv.gif

these help? (check relay switches power for check engine light i suppose, but same deal, L gets grounded when no charging, and has 12V when charging)

[Slim]

The Witzl : I have a voltmeter. However i would like to have the light working also, because i've already put a hole in my dash.

DX20VT : Interesting. I will relay that info to my friend.

WiLo : The whole loom is entirely new so it can't be compared to the original Lucas stuff in any way.

river : Originally the car would have been positive earth and with an alternator i believe. It's a 1967 model but has an MG Metro motor in it.
When i got it, the owner before the one i bought it from had rewired it (poorly) and it was negative earth with a Lucas alternator. The new alternator is a little one (50A) but is probably far better than the rubbish Lucas one it replaced.

[oldcorollas]

oh, there was a site about putting a mitsu alternator on an MG motor...

this one (with pic above)
http://mgaguru.com/mgtech/electric/ac201.htm

[ian]

hi slim
with my vast knowledge of things electric
i can see the problem
the bar code on the alternator is in japanese