dusterbd13
03-07-2011, 09:35 PM
so on the way to church yesterday morning, my wife had the brake (parking brake) and battery voltage lights come on in our 2002 legacy 2.5 GT.
i brought it home, checked the battery terminals, etc. nothing wrong there. took it up to advance, where they ran a load test on the alternator and electrical system. came back that the system voltage was low, either bad alternator or wiring problem.
so i took the alternator off to have it bench tested. 3 different benches registered the alt as good.
put it back on, and check it with my multimeter. alternator has 3.7 ohms of resistance between it and the negative battery terminal. so the alt itself has a good ground. .1 ohm of resistance between the charge wire and positive battery terminal. no jiggling, bending, etc of the wire changed the resistance, so I'm pretty sure where good there.
the light blue and red wire has full battery voltage with the key off, just like the factory service manual says it should. the black/white wire has full battery voltage with the key in the run position like it should, even with the car running.
when i first fired it up to see if the alternator was putting out while in the car, i had a full 14.7 volts at the charge post. it quickly dropped to 12/3, battery voltage. cant make it come back up to charge voltage again.
so, what the hell am i missing here? alternator checks good, I'm getting voltage where/when i should, connections and grounds are clean and tight, etc.
all i can think of is that i may have a bad cluster. in my factory service manual, it shows a diode between the brake warning light circuit and the voltage light circuit. I'm assuming that's why the pair came on simultaneously.
any ideas, guys? I've been puttering around with it for 2 days now, and its time to ask for help.
Michael
i brought it home, checked the battery terminals, etc. nothing wrong there. took it up to advance, where they ran a load test on the alternator and electrical system. came back that the system voltage was low, either bad alternator or wiring problem.
so i took the alternator off to have it bench tested. 3 different benches registered the alt as good.
put it back on, and check it with my multimeter. alternator has 3.7 ohms of resistance between it and the negative battery terminal. so the alt itself has a good ground. .1 ohm of resistance between the charge wire and positive battery terminal. no jiggling, bending, etc of the wire changed the resistance, so I'm pretty sure where good there.
the light blue and red wire has full battery voltage with the key off, just like the factory service manual says it should. the black/white wire has full battery voltage with the key in the run position like it should, even with the car running.
when i first fired it up to see if the alternator was putting out while in the car, i had a full 14.7 volts at the charge post. it quickly dropped to 12/3, battery voltage. cant make it come back up to charge voltage again.
so, what the hell am i missing here? alternator checks good, I'm getting voltage where/when i should, connections and grounds are clean and tight, etc.
all i can think of is that i may have a bad cluster. in my factory service manual, it shows a diode between the brake warning light circuit and the voltage light circuit. I'm assuming that's why the pair came on simultaneously.
any ideas, guys? I've been puttering around with it for 2 days now, and its time to ask for help.
Michael