Alternator DRAWING 5amps

[Pyro]

I think I know the answer to this but I wanna get someone else's opinion before I drop a couple hundred on a new alternator.

I've been chasing down a short in my car that kills the battery overnight. I found out my alternator is drawing 5 amps when the car is off which is more than enough to drain the battery. Is this a sign of a bad alternator? The alternator does seem to put out when it's running. I have the alternator out but If I get it tested that will only tell me if it's putting out voltage when it's running. Should I replace the alternator? The more I think about it the more I'm considering it's time for a 3G upgrade.

 

[HISSIN50]

you can get it bench tested and they can check for a bad diode (which allows juice to flow bi-directionally).

did you have the other thread in which Jerry posted? if so, he and i (i did not post) were thinking the same thing - bad alternator.

i would bench test it first - ask them to test the diodes. that will tell ya for sure what gives and make you feel better about plunking down money for a 3G. be sure to do the wiring and ground upgrades for it.

good luck.

 

[tmoss]

The blocking diode is probably shot. Check it with an ohmeter - red lead on the output post and the black lead on the case.