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Fitted my new 6000k xenons, and my vibe active sub this week. Last night on my way to pick up my g/f from the gym, the warning light (the one with the "check" written underneath) came on.

Planned to get it checked this morning, so dropped my g/f to work then headed down to TPS to get a couple little bits, when i came out it wouldn't start. Got a guy to help me attempt a bump start but no joy, thankfully another random guy has some jump leads which got me going. Got to my g/f's dads garage, and put it on charge there for an hour, whilst i fitted a few bits to the car (put some pics up soon!).

It started ok, but the light stayed on. On checking it with a digital multimeter it read 10v at the battery?!

Alternator on its way out?

Any other suggestions?

Cheers guys.

Maybe your sub is on a constant feed and has been drawing current from the battery all night?.

Then again could just been your alternater dude.

Thought you were a sparky hahaha.

Check is an engine fault - you need to get it on VAGCOM to diagnose

10V on the battery is very low - when running it should be between 13.8 and 14.5

Your battery could be fried, but that wont explain the check light, as if it was an alternator fault, you would get a battery light on the dash

Bradley wrote:Maybe your sub is on a constant feed and has been drawing current from the battery all night?.

Then again could just been your alternater dude.

Thought you were a sparky hahaha.

Ha yeah i am almost, but car electrics are a whole different thing to me!! Im sure i wired the sub correctly.

I also noticed that the wipers and electric windows are working, but at like 1/2 the normal speed.

alexperkins wrote:Check is an engine fault - you need to get it on VAGCOM to diagnose

10V on the battery is very low - when running it should be between 13.8 and 14.5

Your battery could be fried, but that wont explain the check light, as if it was an alternator fault, you would get a battery light on the dash

Yeah i thought i'd have a different light to the one i have. Don't have my mauel to hand to check the name of the light. Hhhmmm, what power should be coming from the alternator? About 14v?

Also just tried to start it now and no joy.

New battery id say mate - asap. Its not holding a charge at all. If you put a multimeter on the main lead from the alternator and ground on the chassis or the battery, you should see around 14V

If you dont, its most likely the battery, but it could be the alternator failed.

Sounds like it could be the battery as Alex said.
Stick it on charge and remove the cell covers, if its charging properly they will be bubbling nicely but if some of the cells are still then its time to get yourself a new battery.

The light is an exhaust emmision warning lamp according to my handbook

It covers many things not just emissions

Ok cool, its just i would of thought my battery light would of been on instead if that one for this problem.

Battery light only comes on when alternator is putting out a voltage below 6V

I see ok. After speaking to my mechanic he said he's pretty sure its the alternator, is it best to get a proper VW one, about £50 more.

I prefer genuine really.

Little point in getting a genuine one - for the GTI its £170. You can get an as new bosch one from GSF for £95
Thats what I have in mine and its working a treat!
Normally I get genuine parts, but on things like that, where its a brand like bosch or hella you know that its a high quality product.

And to be fair - have you tried a new battery? A new soundsystem on a dying battery can often completely ruin it!

£95 you say, that's a lot better than I was quoted.

Yeah I know Alex have had 2 people say its the alternator, a mechanic and the g/f's dad (car body repairer) but after fitting the new audio and uprating the bulbs am stuck as to which it is! Any other way of determining which before i spend out?

I'd much rather it was the battery, price and ease of swapping.

Life without a car isn't much fun

All you can do is pop a different battery in there - borrow one from family/a friend for a few hours, drive around and check the battery voltage whilst running, before you leave and after you return

If its dropped below 12.5vish (minimum 12V) then its a faulty alternator. if its still looking good, you need a new battery