7 replies to this topic

[adcyork]

i've fitted a new alternator today as my battery was always flat and the no charge light was always on. But even after fitting the new alternator the no charge light is still on and the battery voltage is 11.87v with engine running! why could this be? i've checked the 3 wires connection at the alternator and theres no problem with that. so why would i still have a problem. Looking in the haynes manual seems to point the finger at the voltage regulator??

[fikus01]

make sure the brown/yellow wire has 12v on it with the igntion on!! (smallest of the 3 wires) its basically the signal that turns on the alternator!! i cant see it not working!! was the new alternator brand new out of the box?

[Dan]

Check the connections in the instrument pack as well. The bulb is part of the circuit that turns on the alternator as Fikus says. 12v from the battery needs to flow through that bulb to the sensing terminal on the alternator before it will generate power. So the brown/yellow wire should indeed be conducting 12v into the alternator as long as the ignition is switched on. Test it. If it's not then suspect the terminals in the instrument pack connector or a break in that wire.

[adcyork]

i've check the voltage between the small pin with the brown/yellow wire and the alternator body and it reads 0.35v! its a brand new alternator yes that i bought just yesterday. i have had the clocks out just a few days ago so it could well be a loose connection behind them that goes to the bulb could it?

Edited by adcyork, 19 December 2006 - 12:39 PM.

[Dan]

Could well be yes. Try re-fitting the multi plug.

[mk=john]

Alomost all charging problems I have come across have been cause by poor engine earthing. Have you checked this? Its wirth removing the earth strap, cleaning it, and replacing it with some dielectric grease or Vaseline to minimize corrosion.

If it is ure proble, its usually the simple things which can easily be overlooked!

[adcyork]

but would the engine run if there was a bad earth?

[Dan]

I think if the engine earth was so bad that even the volt sensing connection to the alternator (which runs maybe a quarter of an amp) couldn't make a full 12v flow there's no way the starter would even consider spinning. But it can't hurt to try, it could be that I suppose.

Edited by Dan, 20 December 2006 - 03:48 PM.