This fault is driving me barmy if anyone can help drop me a line

92 polo coupe - 80k- 1043cc

battery light comes on when I'm driving have changed the battery and tightened the drive belt, light comes on when driving at low speeds and goes off when giving the engines lots of revs. I think I'm going to have to change the alternator unless anyone has got anything else i should try first.

Cheers

D

If you have a multi meter then set it to V DC and check the voltage over the battery with the engine running. At idle it should be around 14V. If you have to rev the engine to get that then you'll probably need to replace.

Dont rule out wiring though, check you earthing from battery to body, and check the terminals on the alt for corrosion. Trace the main feed from the alt to the battery for signs of splitting or corrosion around the terminal posts.

Is the battery holding charge? should be pretty easy to check this time of year, no problems turning the engine over in the cold?

If you have a multi meter then set it to V DC and check the voltage over the battery with the engine running. At idle it should be around 14V. If you have to rev the engine to get that then you'll probably need to replace.

Dont rule out wiring though, check you earthing from battery to body, and check the terminals on the alt for corrosion. Trace the main feed from the alt to the battery for signs of splitting or corrosion around the terminal posts.

Is the battery holding charge? should be pretty easy to check this time of year, no problems turning the engine over in the cold?

cheers rob

checked the battery and its been sitting at 12.3V tried revving the engine but still sits at 12.3V. The battery seems to be still holding the charge, the voltage is not dropping.

The engine turns over no probs, i'll check the wiring in the morning.

i think I'm going to hve to replace the alternator!

cheers

D

yeah that alts a goner :( sorry bud!