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Model specific boards => Golf mk4 => Topic started by: Dan_GTi8v on 18 May 2011, 19:55

Title: Battery warning light always on
Post by: Dan_GTi8v on 18 May 2011, 19:55
Tried 2 alternators and battery light is still constantly on with engine running. Any ideas what it could be? It's an AUM in a mk3 so I dont have the fusebox on top of the battery and fairly sure there is no fuse or relay for it

cheers
Title: Re: Battery warning light always on
Post by: stevelfc on 18 May 2011, 20:27
is the belt and battery itself any good
Title: Re: Battery warning light always on
Post by: Dan_GTi8v on 18 May 2011, 20:39
belt is good, battery was good when it first started but I've now been running with it for a week so have manually charged it 4 or 5 times. Was hoping the new alt today would fix it but no luck :(
I'll be getting the alt tested on saturday with a multimeter on the battery but dunno what else to check  :undecided:
Title: Re: Battery warning light always on
Post by: richw911 on 18 May 2011, 20:50
How much voltage is at the battery with the engine running?
Title: Re: Battery warning light always on
Post by: Dan_GTi8v on 18 May 2011, 21:22
wont know this till saturday :P But as its my 2nd alternator was just wondering what else I could check :)
Title: Re: Battery warning light always on
Post by: richw911 on 18 May 2011, 21:24
Quote from: Dan_GTi8v on 18 May 2011, 21:22
wont know this till saturday :P But as its my 2nd alternator was just wondering what else I could check :)

Wiring to the alternator? The plug?
Title: Re: Battery warning light always on
Post by: Dan_GTi8v on 18 May 2011, 21:55
Plug looks fine, I guessed it would be ok as the light comes on. wiring is fine as far as I can see, but can only see it as far as the battery then it goes into the main loom. Everything is pointing towards the alt being shagged I guess :( Just sux I only got this one yesterday :( I'll update on saturday with the rusults of multimeter on battery
Title: Re: Battery warning light always on
Post by: Wayne on 18 May 2011, 23:48
Check and see if it is charging as a 1st step.
Title: Re: Battery warning light always on
Post by: Dan_GTi8v on 19 May 2011, 16:12
It's deffinatly not charging, I've been putting it on a manual charger after 3 or 4 trips and its always on around half power. I'm keeping an eye not to overcharge the battery but not sure how much longer its gonna last  :undecided:

Should be putting a multimeter on it tonight, also been suggested to run 12v to the positive pin on the plug and if it charges just swap over for my old mk3 alt which only has 1 wire going to it instead of the 2 on the mk4 alt
Title: Re: Battery warning light always on
Post by: Ant1981 on 19 May 2011, 16:35
Rectifier.
Title: Re: Battery warning light always on
Post by: Dan_GTi8v on 19 May 2011, 17:54
Problem solved! although I'm a bit embarassed to say what the problem was lol  :embarassed:

When wiring in my loom I 'accidentally' wired in the big +ve wire to the neg terminal on the battery  :grin:

Now I'm off to bow my head in shame