9 replies to this topic

[miniboy94]

hi there having some issues with my charging system, right i changed my battery and alternator about 2 mouthes ago at the same time but the other day my battery went dead i charged it and tested it with the multimeter iderling off load was around 12.7V and going up very slowly but not flucuating at all, once on load it just kills its goes strait down to 10V ? i got told to cut the thin brown and yellow wire at the back of the alternator and earthed it to see if the light yellow lit up as i got told it was my charging warning light but it didnt light up with igniton on or when running, but i did find that when i cut it the red one didnt light up at all so i fort the wiring is arse about face if that makes sence so fair ? but i carnt work out what is wrong with it now, do i need to add an extra earth lead to help it charge under load or do i need to take my alternator back to the shop and swap it ? but once ideling for so long the red light on the dash does light up but onced rev'd the red light will go off again ? any help would be great really confusing are wiring diagrams haha

 

thanks ben

[cambiker71]

Sounds like a duff alternator, but first with the engine off and ignition on does the red warning lamp come on? (yellow one is oil pressure!) 

If not fix it so it does and earths down through the alternator with ignition in/engine off

if so start the engine, does it go out? 

No= not charging

Yes =charging

if it goes out when revved then check voltages when revved, but still sounds like a duff alternator, where did you buy it two months ago? If it was a good motor factor then they'll know what readings are supposed to be good so take the readings with you when you take it back for replacement, if it was a breaker then go with cash for another!!

 

good luck!

[KernowCooper]

Check the small brown wire and with the ignition turned on there should be 12v present, and with this wire earthed the red light (Ign) should come on, if it does so then the cars exciter wire to the alternator is working correctly.

 

Your batttery voltage reading indicates that the alternator is not charging.

 

I would now remove the plug on the rear of the alternator and check the connectorsof the larger brown wires are not burnt or loose and check the other end at the starter solenoid.

 

You dont mention the age/model of your car but the later cars had a fuseable link in the large brown wires, do a check for contuinity between the ends of the large brown wires, if open circuit locate the fuseable link in the wires and replace, they are marked Hypalon’ on the insulation. These can be replaced with 60amp  mini fuses and repaired.

Edited by KernowCooper, 24 January 2014 - 10:38 PM.

[miniboy94]

hi there guys when the igniton is turned on the red light shows up once running it does go off but once every like so often dosnt go off untill reved but then it want do it again for agers and i mean like a mouthe or two ? i got the alternator of ebay it was brand new upgraderd 75amp i belive and i messeged the bloke and he said if you send it back he will test it and let me know like and if it is faulty he will send me out anther one ? and wires all seem ok not are slack in the connectors and iv cleaned the terminals up up just to be 100% sure that it isnt them and the car is a 1990 mini mayfair iv only just in the past 3 mouthes started having issues with my battery and alternator and it is starting to do my head in i just fort it had somthing to do with the extra's i run on my car eg:spot lamps ciggerate lighter and cd player and that it just couldnt keep up with them but even nowin day light when nothing is on it will die on me

[grumpy dad]

Hi 

yes it sounds like a duff alternator 

sounds like a dry joint in the diode pack

your problem will be if it works when you send it back to the guy

that's why I shop local  

it might cost a bit more but you all was  get same day service 

[miniboy94]

hi grumpy dad and ow right is there any test i can do my self to see if it is dead or not ? carnt really afford to send it for them to say its fine but still be ******* bard once sent back to me again :/

i might see if i can borrow my mates alternator and run it round the bloke for a while see if it puts some charge back into the battery others wise im taking it to auto electrition lol

[KernowCooper]

Here is all the diagnostic tests for your alternator http://www.theminifo...ng-basic-tests/

 

If it fails on any of the points relating to the alternator its self then its faulty

Edited by KernowCooper, 04 February 2014 - 11:45 PM.

[Mr Joshua]

Ignition barrel. Think about it. Run your car on load if the black box is getting warm to the touch it's worn out change it problem solved.

Sounds to far left field but I put three alternators on mine with no change had them all tested and they all came back as100% serviceable. A wiser man than I told me to change that 6" bit of loom and my charging problem vanished.

Edited by Mr Joshua, 05 February 2014 - 01:59 AM.

[KernowCooper]

If you've done the continunity tests on the loom between Alternator Plug and Solenoid connection and its ok, then do the alternator tests in my post above

[miniboy94]

cheers guys il do this at the weekend when i get a spare minute lol

"kernow cooper" appreate it a lot mate for the testing stops me from making it complecaterd haha and thank a lot very one ealse really do appreate it a lot