My battery warning light keeps coming on, but if I rev the engine it goes off.checked the belt its ok what do you think,

If its an alternator fault is there a brush pack available from Halfords??? and how easy is it to change them, or do they carry new one and how much roughly

Would it be ok to run it as I need to get to Newcastle twice on Monday

Edited 5 February, 201115 yr by skippy41

Check the alternator wires, especially the sense wire (probably blue) for a break.

Battery went dead all warning lights even steering wheel one just as I was going round a corner had to use brute force to get it round and to keep it on the road.

Have called AA hope its just a duff battery

My money is still on the alternator not charging. Check the cables, get the AA man to check charging.

You can't check the alternator without first checking the battery is OK. A good alternator will not charge a bad battery.

It could be reverse leakage on the alternator. If it is that then it will drain the battery. The best way to check an alternator is to take it to a specialist who can put it on a jig and run it - I used to do that many, many years ago when I worked for the old Lucas Automotive!

I think I'd go with the Alternator being at fault

Rich

AA has been and got me going, he jumped started it gave the alternator a good tap with a hammer and you could hear the alternator suddenly kick in, and start charging the battery, he then checked the output it was 100%

Outcome new alternator required or a brush pack if you can get one, if not how much would one be???

All warning lights went off once running

AA said get a higher power output one if possible due to all the taxi equipment, anyone got any part numbers???

Edited 5 February, 201115 yr by skippy41

Check voltage output from alternator at battery terminals. With engine at about 2,00 rpm and all lights , heated rear window, aircon etc on , the voltage should be greater than 14V . Idealy about 14.5V. If output is low then new regulator assembly (brush pack + voltage regulator) may fix problem . Check brush length against Haynes manual spec. If brushes are too short they will not have sufficient spring pressure to give good electrical contact . New regulator is about £20 to £25 for reputable make - a lot cheaper than new alternator !.

Edited 5 February, 201115 yr by vwcabriolet1971

New regulator is about £20 to £25 for reputable make - a lot cheaper than new alternator !.

Can you get a regulator pack from Halfords, and how easy are they to fit???

Can you get a regulator pack from Halfords, and how easy are they to fit???

You would have got one about 15 years ago, try Unipart or GSF ,

Curiosity got to me found this http://cgi.ebay.co.uk/VALEO-ALTERNATOR-12V-REGULATOR-VW-AUDI-SKODA-1045-/300392641274?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item45f0cbf2fa

Edited 6 February, 201115 yr by patrol man

Anyone any idea as to how much an OME alternator costs????

Check the alternator clutch as it's part of the alternator that can be changed without replacing the whole thing (about £70) and is something that does go.

Before ordering a regulator pack make sure you have all the alternator details, i.e. Make ( Bosch or Valeo ), part No. of the alternator ( should be on the regulator or sometimes there is a barcode label on the alternator with P/No ), and the capacity ( 120A or 140A ). Supply all this info with the order. If the regulator P/N. is on the regulator supply this P/No. also.

AA has been and got me going, he jumped started it gave the alternator a good tap with a hammer and you could hear the alternator suddenly kick in, and start charging the battery, he then checked the output it was 100%

Outcome new alternator required or a brush pack if you can get one, if not how much would one be???

All warning lights went off once running

AA said get a higher power output one if possible due to all the taxi equipment, anyone got any part numbers???

Skippy,

The AA man probably meant a higher output battery. The output rating of your existing alternator will be fine (if it's still good) but it's probably having to take the slack for an underpowered battery. If you have a lot of ancillary electrics running you may be placing too great a load on the battery. Especially if you turn the engine off regularly for odd periods but keep the gizmos powered on. Even worse if it's a diesel (glow plugs are current hungry). If you're using the stock battery it probably doesn't have enough grunt to repeatedly crank the engine and then power all the extras you have. The alternator is working it's socks off delivering charge to the battery and running your electrics till the battery is back up to speed.

Your alternator is designed to pump out high current only when it's required i.e the regulator monitors the battery and the stator (electo-magnet bit) and increases the field current to the stator when the voltage drops then decreases again when it rises to healthy level. If your extra electrics are pounding your battery and demanding a lot of current during charge cycles your alternator is probably working flat out most of the time. This means the diodes and windings are taking more punishment than they need to which will shorten the alternators life.

Whatever you discover is the actual problem you should think of upping the battery to something beefier - 70Ah. It'll be £80 to £100 well spent. Your alternator and battery will both live longer even if you regularly sit for a while with the engine off listening to two radios whilst waiting :-)

I got it changed and a new belt, £350 fitted :S

Mechanic showed me the bearings had gone, I did mention that I did hear a grinding sound the day before