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No Batt Warning Light


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#1 robminibcy

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Posted 31 October 2014 - 08:27 PM

Hi all,
Had to jump start mini tonight so took for a drive to give it some charge. Drove about 5 miles then stopped to check what had fallen over in the boot and it cut out as I tried to pull away A mate came out to jump it and it started straight away, but cut out as soon as lights were turned on. Tried to jump again and I noticed I had no ignition light on. Checked batt and alternator connections and changed ignition warning light bulb to no avail. Borrowed the battery from a mates yaris to get home and the ignition warning light was lit but very dim. From these findings would it seem I've fried the alternator.
It regularly has to charge the battery from completely empty as the battery is very worn out. I've not been able to check voltages as the minis battery is to flat to start it at the moment.

Cheers


Edited by robminibcy, 01 November 2014 - 12:19 AM.


#2 KernowCooper

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Posted 31 October 2014 - 09:10 PM

If the light is not on when you turn the ignition on and then dimly lit when running it indicates a fault with the diode pack in the alternator. Switch the ignition on and remove the plug from the alternator and put a wire onto the SMALL SINGLE WIRE this should then make the ignition light come on, DO NOT TOUCH THE 2 LARGE BROWN WIRES THEY ARE LIVE.

 

You have 2 choices either get a diode pack and regulator kit and solder it in yours, but depending what yours is like and age it may be cheaper to get a new exchange unit.



#3 robminibcy

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Posted 31 October 2014 - 09:19 PM

My alternator only has 1 connector with the 2 large wires and the small one. Should I unplug it then put a wire between the small connector on the plug and the small one one the alternator? I just want to confirm its faulty although I suspect it is as its taken some abuse! I will fit a spare I have as the currect has some play in the shaft. I need to swap the pulleys over as they are different sizes. The spare also has a single connector as well as the large one with 3 pins, what I the additional single pin for?

#4 KernowCooper

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Posted 31 October 2014 - 10:00 PM

Just put a wire on the SMALL TERMINAL/WIRE and the other end to earth. check the light =on is faulty diode pack



#5 robminibcy

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Posted 31 October 2014 - 10:13 PM

Ok, thanks very much, ill check when its light tomorrow.

#6 robminibcy

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Posted 01 November 2014 - 11:48 AM

Done the checks with a known good battery from a golf. The light is fine and came on when earthed, then I plugged alternator back in started car and light went out straight away, checked voltages and I'm getting 12v switched off and 14 running which sounds pretty much spot on. Could it be then that my battery is so worn now the alternator just couldn't keep up last night?

#7 Dan

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Posted 01 November 2014 - 12:25 PM

If the battery is so low that the ignition lamp doesn't light then the alternator won't start charging, it needs to have a reference voltage.




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