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Fishmaster-zero
28-09-2007, 03:50 PM
Hi i've got a 2002 passat 2.0 20v 130HP

When I bought it I had an alternator problem and bought a new one,

this is now fitted however over the last few weeks abs waring lights have started coming on when im in traffic.

I called the AA and the only problem they could find is a drop in voltage when at idle speeds and ive got the Climate control on. With just the Climate control and headlights the volate drops from 14.2 to 12.1, and with the heated screen on it goes down to 11.8v.

I've had the alternator replaced under warrenty but the problems still there.

I changed the battery and still no problem

I cant find a bad earth anywhere, and when reved the alternator is capable of 14v no problem, its just at idle.

The garagem who supplied and fitted the alternator are a general electrical specialist and claim that no two alternators could have the same issued and that the regulator is functioning correctly.

they are currently investigating the car but are at a loss to the problem.

Does anyone have any suggestions on how I can get this resolved or what could be causing this problem.

The bigest drain in the climate control but it seems to function perfectly?

Please help if you can!

Martin :aargh4::1zhelp:

lobsterfunk
05-01-2009, 09:36 PM
Hi there - did you ever sort this out as my Passat is doing the same? At idle revs in cold weather the headlights and dash lights all flicker. As soon as there is some revs, the lights go bright and solid. Problem goes after 20 mins when car is running warm.

Many thanks

snapdragon
05-01-2009, 09:42 PM
This is usually one of the diodes has failed in the rectifier pack, this means that the alternator is only changing on part of it's revolution, and so the output will be low and in pulses.

njek
05-01-2009, 10:04 PM
Apologies for my ignorance, but is this therefore a problem with the alternator, or with another component? (I have no idea what the rectifier pack is)

snapdragon
05-01-2009, 10:11 PM
Yes, it is usually a pack mounted on the alternator with nuts (which the wires come out of) and on most cars you can hopefully replace it without removing from the car, but I have no experience with this on these cars, just a general alternator issue.

caldirun
06-01-2009, 09:00 AM
Hi i've got a 2002 passat 2.0 20v 130HP

When I bought it I had an alternator problem and bought a new one,

this is now fitted however over the last few weeks abs waring lights have started coming on when im in traffic.

I called the AA and the only problem they could find is a drop in voltage when at idle speeds and ive got the Climate control on. With just the Climate control and headlights the volate drops from 14.2 to 12.1, and with the heated screen on it goes down to 11.8v.

I've had the alternator replaced under warrenty but the problems still there.

I changed the battery and still no problem

I cant find a bad earth anywhere, and when reved the alternator is capable of 14v no problem, its just at idle.

The garagem who supplied and fitted the alternator are a general electrical specialist and claim that no two alternators could have the same issued and that the regulator is functioning correctly.

they are currently investigating the car but are at a loss to the problem.

Does anyone have any suggestions on how I can get this resolved or what could be causing this problem.

The bigest drain in the climate control but it seems to function perfectly?

Please help if you can!

Martin :aargh4::1zhelp:
Have they fitted a genuine alternator or just a cheap generic one with the wrong diameter or type of pulley, sounds like its low alternator revs thats the prob, did it have a one-way pulley on before the change, has it now?