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Discussion Starter #1
Hi any idea how to test the alternator? i have a 04 lwb 130, left van parked up for 6 weeks and other day when i came to use it the battery light stayed on for a while before eventualy going out, i used it all day and all seemed fine. Came too use it today and drove 20 miles and battery light is on permanently now and tested the batt while its running with a multimeter which reads about 12.3 volts. I read a thread about the gates coupling so i removed the undertray and looked from underneath but it looks to be spinning fine when the engine is running, fuses look to be ok too in fusebox. is there anything else to check? Any info would be appreciated
 

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The coupling might be spinning but is the alternator rotor itself ?

If you can get to the alternator check you have 12v getting to the alternator from the battery with the ignition and engine off, basically making sure you have a good +ve connection. If not check the fuse under the plastic cover on or next to the battery +ve. Check both sides of fuse and they should show up as 12v again with ignition off. If not fuse may be faulty or loose. If okay start vehicle and check voltage, should go up to about 13-14v. If not then alternator is at fault and may need to be removed to get checked , or replaced T:
 

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ok thanks for the advice i will check those things tommorrow, the alternator rotor is definately spinning. you say check the voltage at the alternator, where exactly do i probe it? i can see a black plug with 2 wires coming out but looks fairly well sealed and a larger wire nutted down to the body, i presume this is the earth? cheers :)
 

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ok thanks for the advice i will check those things tommorrow, the alternator rotor is definately spinning. you say check the voltage at the alternator, where exactly do i probe it? i can see a black plug with 2 wires coming out but looks fairly well sealed and a larger wire nutted down to the body, i presume this is the earth? cheers :)

The larger wire with a nut holding it on is the 12+ve lead, and that is the place to check if there is a supply to. The alternator doesn't have an earth wire as such as the body is the earth (or -ve) T:
 

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Discussion Starter #6
Right checked everything you said today and 12v to alternator with ignition off and still 12v when its running, looks like it must be the alternator that has gone. I read that these alternators on this model have a seperate regulator on the alternator body so would it be possible to remove this while it is in situ? Would this be a worth trying before removing the alternator? i called into an independent garage today and he told me from his computer that it would take 2.2 hours to replace the alternator if the job went smoothly but they had never done one before, thinking of having a go myself if i cant just swap the regulator in situ?
 

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When you checked the voltage across the battery, with the engine running, was the engine just idling ?
You might need to increase the revs a little, just to be sure the alternator is at fault. If you start the vehicle, get someone to hold the revs to about 2000 & check the voltage across the battery it should be around 14v.
More than likely it's the alternator, as previous posts have said T:, but it might just be worth checking.
 

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Discussion Starter #8
The voltage stays pretty much the same when its reved at about 12.2v, any idea how easy the alternator is to remove? cheers
 

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Definately the alternator at fault then, as someone else has already
Sorry, not sure about the 2.5's. Mine is a 1.9 & was a bit of a pig to get off (access mainly the problem). I'm sure they don't have a belt driving them, it's some sort of coupling, forget what it's called. It may be just a case of removing the alternator mounting bolts & drawing it away from the coupling, but I can't swear to it.
I also think I've seen posts before suggesting replacing these couplings when items are removed/replaced, but again don't really know what is involved. Best to check with someone more knowlagable :)
Be sure to disconnect the battery before starting to disconnect the alternator, or at the very least remove the big 175A (I think) fuse on the B+ wire. You don't want that big cable flopping around in the engine bay, live :eek:
 

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The voltage stays pretty much the same when its reved at about 12.2v, any idea how easy the alternator is to remove? cheers

No idea , but as CAT says, disconect battery first. Once off you could just get it repaired, it may just be something cheap, brushes or something.
 
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