My wife reported that her 2001 MK4 Golf V6 4motion reported an "Alternator Workshop" warning the other day. I've just checked the voltages and the battery voltage is 11.8v which rises to aroud 13.4v when the engine is running. This doesn't change if you rev above 2500rpm. I've checked the battery cables and the ones in the little fusebox on top of the battery and they look ok (though I haven't tested the voltage drop which I meant to do) but I can't get anywhere near the alternator itself as there's a whacking great V6 in the way lol The battery voltage is a little low at 11.8v (probably because it's not charging well/at all) but it does seems that the alternator is doing something as the voltage rises to 13.4v when the engine is running. Faulty voltage regulator, perhaps? Or worn brushes? Any ideas what I can check next to diagnose further? I don't want to replace the alternator unless I'm sure it's faulty as it's a full front-end strip-down by the look of it.
Recheck the charging voltage with ALL electrical loads turned on (full heater speed/all lights/heated rear window/radio/wipers...the lot) It should still hold above 13v. If not the alternator is fubar.
They are hard on batterys I've had two Bosch ones in the last 4 years The alternator went on mine last year was not a bad job aye the front needs to come off I just pulled the forward leaving it hanging
Where are they on this? Can't see anything with this damn engine in the way! Checked the connections in the fusebox on the top of the battery, all looks good with no voltage drop.
Our Bora VR5 (AQN) engine had the same issue and the alternator had to be replaced. Failure is common!
Is it worth replacing just the voltage regulator module? Or just bite the bullet and replace the whole unit?
Replaced the whole unit with one from a breaker cheaper than a replacement voltage regulator module was. That's a tight fit between the engine and the front panel isn't it! Even when you pull it forward as much as you dare. All working now, 14.4 volts on load and both arms covered in bruises!
Aye it's a fun job lol Not sure what went on mine brush's where fine but suspect it was the voltage regulator I had to change the battery just before hand as it was not holding charge anymore Mine packed in as I booted it away from the lights I now have the bigger r32 one fitted now Aye Eddie all too common guess they get a hard time over the years Can't complain mine was on its original alternator and battery when I got it
