My cars battery was dead this morning so I jumped it but noticed that the battery light was not coming on on when the key was turned,I've checked the bulb and the alt connections and all seems fine? any ideas?
thanks

Since the light does not come on when key "On" but not running, it does sound like a charging circuit problem. Most of the time its just a bad bulb. How did you check the bulb?

I switched bulbs around with the ajar light,both bulbs work in that socket but not in the battery socket so I assume the bulb is good.

OK, take a look at the wiring diagram: http://www.euronet.nl/users/fo_elmo/fiero10.pdf

Time to take some voltage readings. With the key "On" you should 12v on one side of the bulb with pnk/blk wire, not both sides. This wire also should feed power to the rest of the instrument cluster, does everything else work? The brown wire should not have 12v on it until the engine is running. Check the wires on the alt for 12v, the red wires. If you don't see a problem it may be time to take the alt in to be tested or replaced.

Odd thing is I have power on the pink/black wire with the key off ? also would the fact that the bulb isn't lighting be an indication that theres a problem in the charging circuit and not the alt? what is the function of the two wires in the circuit?

[This message has been edited by samt (edited 11-26-2005).]

Interesting, is there power there when the fuse is removed (the one for the instrument cluster).

The "Charging" circuit contains the regulator, which is inside of the alternator.

I'll have to check that in the morning when its light,one question though is it not true that the pink/black wire is pulling voltage from the instument panel (battery light) when the keys turned? to tickle the alt?

[This message has been edited by samt (edited 11-27-2005).]

For the bulb to come on the pnk/blk wire should be 12v and the brn wire should be very low or at 0 volts. With key on and engine off, measure the brown wire at the alt or at the bulb, if its 12v the problem is most likely the regulator in the alt- replace the alternator. Also in any key position there should be 12v on both red wires on the alt. You could try cleaning the connections on the alt.

I don't understand if the power comes from the bulb circuit how can I have voltage at the alt connector and no battery light? will a bad alt cause the battery light to not light? seems to me the day this happened things weren't normal such as the power window was very slow and the wipers were slow (while driving) some noise coming from the alternator.This very same thing happened to me right after I changed my water pump but after pulling the alternator connector and plugging it back in the battery light came on.

Think of it this way, if you have 2 wires coming from the battery + terminal, the voltage measured from each of the wires to ground will be 12v right? But if you add a light bulb between both + wires what happens? The bulb won't light because there is no voltage difference between them. So, when you are measuring the voltage on the pnk/blk wire you are reading 12v to ground, if you are measuring 12v on the brown wire to ground then there is no difference in voltage- no light will be on. What voltage are you reading on the brown wire that goes to the alternator? If 12v it sounds like you need a new alternator.

Since you said that everything ran slow before this happened it sounds like at that time your alt wasn't working and you were running 100% off of the battery and it was dying.

I have 11 volts on the brown wire at the alt connector, I read else where that if I ground the brown wire at the connector and the battery light comes on with key on then the alt is bad? so that means that the alt can cause the light to not work,sorry I know nothing about wiring I was just a little confused when I found power on the brown wire at the alt but no battery light I thought the bulb needed to light to feed power,.Its all starting to make more sense now thanks.I'll do the ground test and see what I get.

Before you try to ground the Brown wire you should unplug it from the alternator. My guess is that your regulator has a short to the brown wire. If you just short the brown wire without unplugging it you may see alot of sparks. This test will only show that the bulb part of the circuit is working. This would mean that its time to replace the alternator- also get your battery tested to make sure it is healthy.

[This message has been edited by Ken_86gt (edited 11-27-2005).]