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coppiceno1

Member

• Oct 30, 2009

• #1

Does anyone know why my disco 200 battery light on the dash doesn't come on ,charged battery but light didn't come on

 

nathan5346

Well-Known Member

• Oct 30, 2009

• #2

U checked the bulb?

 

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coppiceno1

Member

• Oct 30, 2009

• #3

i think it might be alternator,because battery went flat

 

nathan5346

Well-Known Member

• Oct 30, 2009

• #4

And the battery light s'pose to come on when alternator packs up? Check the bulb

 

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coppiceno1

Member

• Oct 30, 2009

• #5

yeh best go for the easy route first

 

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martinhollings

New Member

• Oct 30, 2009

• #6

there is a fault in the alternator that can cause the light not to come on when it should but still wont charge just can not rember what it is (diodes i think)

 

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colinl

New Member

• Oct 30, 2009

• #7

the battery light wont come on if the regulator in the alt is knackered or could be rectifier (diode pack) feeding back which also discharges the battery.Either way you need to take the alt off and have it tested.

 

fanatic

RESPECT IS EARNED, BEATINGS ARE FREE ;-)

Forum Sponsor

• Oct 30, 2009

• #8

Or shorting the sensing wire to earth should light lamp, unless you have blown bulb

 

ntfs

Member

• Oct 31, 2009

• #9

Like Fanatic says, earthing the sense wire (thinner brown/yellow wire from back of alternator) with the ignition on should light the warning lamp. If not the lamp could be blown or the wire broken somewhere.
The lamp supplies the field current to provide the initial output when the alternator spins up after which the alternator provides the current through three of the nine diodes in the rectifier pack. It is quite likely that either the pack has failed or the brushes are totally worn in which case a new alternator is needed (likely if it's done a big mileage).
I had similar symptoms a while back - new alternator cured it.

 

mickdj

New Member

• Oct 31, 2009

• #10

check the bulb if that is ok ground the d+ wire and the light will come on if it dose it the alternator if it dosent theres a wirering problem and the alternator isnt exciteing.

id ground the d+ first as it would be easyer than pulling the dash out.

 

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coppiceno1

Member

• Nov 3, 2009

• #11

as repied to,had to get another alternator,thanks for all the help,cheers

 

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Jamesyboy

New Member

• Nov 19, 2009

• #12

Hello guys - a great wee thread with lots of useful suggestions. I used the earth test to check my battery warning light - it came on. So my alternator is not charging but it is also not telling me! Don't you just love it when trouble comes in threes??? Battery done in, alternator down, and no light to tell me the wiser!

So I too am off to get me one!