Would be a good idea if I had a trunk light. + for the attempted help though

Woohoo! progress. Fresh battery and start checking stuff. L terminal shows 12.6V with the ignition off.

quote Originally posted by Marvin McInnis: First check: As TK suggested way back in February, disconnect the regulator plug at the alternator and check the voltages present on the pins. With the ignition switch off, is there still +12 volts at the "L" terminal of the plug? If yes, continue below. If no, there is probably a wiring problem at the plug itself. Does the "L" wire on the plug actually match the correct "L" position on the alternator? Not all alternators are the same. Second check: You need to check the entire circuit from the ignition switch to the "L" terminal. Is the "Alt" lamp on constantly, even when the ignition switch is off? If yes, then either 1) the ignition switch is bad, or 2) there is a wiring problem between the ignition switch and the lamp. If no, then either 1) the lamp is burned out or missing (replace it and check again), or 2) there is a wiring problem between the "Alt" lamp and the alternator. Let us know what you find.

So Mr.McInnis was right. Someone give this guy another plus for me. Now how would I go about testing the ignition switch? Checking the bulb should be fairly simple. Pull out the aux pod and check the bulb. If its a wiring problem I'm definitely going to have to find someone who can do that >_<

quote Originally posted by spark1: Here is a comparison of the two alternator types; the Fiero is on the right ...

Just a minute!!! That's not the correct alternator wiring schematic for the '88 Fieros. The CS-130 alternator does not receive field excitation current through the "L" terminal.^* Most of what follows was originally posted in this thread. The schematic below was copied directly from the '88 FSM.

The three wires in the harness connector to the alternator (per the 1988 FSM) are used as follows:

S terminal (3mm red wire) -- Voltage sense (based on the wire size, it may also be a backup path for field excitation current)

F/I terminal (0.8mm brown/white wire) -- Ignition switch position sense (hot in run only)

L terminal (0.8mm brown wire) -- "Charge" indicator drive (this is NOT used for field excitation current on the CS-130)

P terminal (no connection) -- "Pulse/phase" output (12 volt square wave, indicates alternator rpm)



This still leaves open the question why Silentassassin185 is seeing voltage present on the "L" terminal of the connector when the ignition switch is off. The only terminal that should have +12 volts on it when the ignition switch is off is the "S" terminal. Is it possible that the sense (red) wire is somehow shorted to the indicator (brown) wire either at the connector or back up in the wiring harness?


^* From the '88 FSM: "When the Ignition Switch is placed in RUN, voltage is supplied to terminals L and F, turning on the Regulator ... The digital regulator controls the Charge Indicator light with a solid state driver. The driver turns on the light whenever undervoltage, overvoltage or a stopped generator is detected."

[This message has been edited by Marvin McInnis (edited 09-08-2009).]

Rain today and forecast until sunday is rain. Watching the other thread and look into that situation next day its clear out.

So my diagram is no help?

Bump my man, I am thinking we need to sweet talk Marvin, and take a little road trip to KC .

Brad

Started the car up tonight to go to work and realized the Battery light didn't come on when I switched the key over but didn't start? Maybe something maybe nothing but next clear day it isn't raining I'll be digging into the dash checking for a burnt out bulb just in case.

Sorry, but you're grasping at straws (or hoping for a miracle). There is no way a missing or burned out Charge Indicator lamp can be causing your battery drain. You need to study and try to understand the '88 alternator wiring schematic; it's not that complex a circuit.

[This message has been edited by Marvin McInnis (edited 09-11-2009).]