OK I give in (charge light staying on)

[Hacksawbob]

Replaced and cleaned gearbox and engine earths ( 2.1 syncro), and the charge light still stays on on the dash, charging battery fine alternator was replaced 6 months ago (according to seller)and fan belt good . Any ideas?

[Anonymous]

Bob,
Have you measured the voltage from the alternator using the engine as an earth? Should be between 13-14V when the engine is revving (i.e. not ticking over).
Could be that the brushes just need changing or something more involved.

I'd take a trip to your local Alternator/Starter motor repair shop and ask them to put their tester on it while its running. Most places are happy to do this as if there's a problem, you're most likely to go back to them.

I usually have alternators and startermotors repaired rather than replace as its usually in the region of £25 or so and its guaranteed for a year.

Oh... just remembered, its possible that the alternator is not earthing properly to the engine, sounds nuts but I've had this happen a few times despite it looking fine and being bolted in tight. Take it off and clean up all the surfaces.

MG

[Hacksawbob]

cheers mike I'll give the alt a clean tommorrow and test against the engine block.

[stuckin88]

If its the original Bosch alternator--brush carrier/regulator is easily removed-2 screws--minimum brush lengh-5mm--new one-£15

[tonytech]

Has any one used the alt light circuit to trip the split charge system? Check the wireing is in place.

As I remember the alt light has a +ve feed and the alternator earths it when not running. There is a diode in the alternator that can blow if too much currant is taken from this feed.
Can you get a voltmeter on the back of the alternator?

T

[Hacksawbob]

Hi I ran a separate earth from the body of the alternater still no joy, Its on the caravelle so no split charge Tony. Voltmeter is reading 14 volts from the back to the engine block at tick over. changed the belt whilst I ws there too.

[angry vanagon]

if the light is on all the time either the thin blue wire on the alternator is shorted to earth to test pull blue wire from alternator with ignition on. if the lamp stays on the problem is a shorted to earth blue signal wire you will need to follow the wire from the alternator down it length till you find it trapped or insulation rubbed through (p.s. if it stays on with wire disconected from alternator check if a split charge relay has be fitted if it has disconect its alternator feed wire as this could be holding the light on) if the lamp does go out when the wire is disconected then the alternator likely is the problem most likely to be a faulty diode or brushes a bad earth would cause the alternator charge lamp to not light at all hope this helps

[Mocki]

replace the brush pack, if blue wire trace proves friutless.....99% of the time its the regulator at fault

[Hacksawbob]

thanks I'll take a look when I get a mo, do you know where I can get the brush pack? I wouldn't have thought it was the alt as it looks shiney and I have a receipt from the seller saying it was replaced in the last year.

[Hacksawbob]

right oh, blue wire off, charge light off. so whats next, brushes? GSF dont do them any ideas?

[Aidan]

Bob, you may have a 90 amp alternator, slightly different to the 45 and 60. Do you have a threaded stud as a positive on the back of it ? I'll ask my local alternator man tommorrow when he checks mine out.

[Hacksawbob]

Cheers Aiden, yes the post is a nice thick threaded bolt pos 10 or 12mm nut. it has T10 printed on the side, there was a sticker that had a barcode but I rubbed it to clean it up to read and all the printing came off the plasticy label