My dashboard alternator light is staying off,the excitor wire terminal is getting the normal 10V but the terminal for the alternator light is only getting 0.5V ,what is bugging me is that if the coil in the voltage regulator for the alternator light was shorted out, would that not mean that there would be no voltage,I have little to no experience on alternators so any help would be much appreciated.

Edited 18 May, 201016 yr by WeekendMechanic

Where is the "terminal for the alternator light" that you're talking about? What car is it? My Fel (and indeed favs) only have the one connection (other than the output to the battery, obviously).

From a handy Haynes (Citroen ZX, but all alternators are similar):-

If the ignition/no-charge warning light fails to illuminate when the ignition is switched on, first check the alternator wiring connections are secure. If satisfactory, check that the bulb has not blown, and the bulbholder is secure. If the light still fails to illuminate, check the continuity of the warning light feed wire from the alternator to the bulbholder. If all is satisfactory, then the alternator is at fault.

if its a felicia or fav remove the small wire to the altenator (yellow or green i think) and with the ign on earth it on to the engine somewhere with a bit of wire or an old paperclip while someone else watches for the light to illuminate on the dash, if no light then either the bulb is blown or the wire broken (felly's break where it joins the loom) if it does light up then it probly needs the reg pack changing in the alt.

ps it wont charge properly unless the light is functioning correctly

k.... has anyone ever opened a reg pack up before,whats is inside :wonder:?

Edited 18 May, 201016 yr by WeekendMechanic

No point, just replace it. Have you done what Jim has suggested? That's the way to tell if it's a fault with the car's wiring or with the alternator itself....