91 pontiac grand prix power problem

Hopefully your alternator is producing more that 14 amps period or you have a problem either way.

yes i'm sorry i meant volts. It's weird, of course the battery goes down very slowly if none at all during the day but goes down very fast when I use the headlights. So the alternator might be good but the battery bad i'm thinking as when the car's running it should be running off the alternator and of course the headlights run off of the battery. It sounds to me almost like the alternator is running fine but the battery isn't holding a charge correctly, even though it tested fine before i put it on the car and after i drop for 4 blocks with it on. But why would the alternator read at 14 volts off the car in a test and 12 on the car? Am i going to be forced to have it put on a machine to test it and see exactly what is wrong with it?

yes i'm sorry i meant volts. It's weird, of course the battery goes down very slowly if none at all during the day but goes down very fast when I use the headlights. So the alternator might be good but the battery bad i'm thinking as when the car's running it should be running off the alternator and of course the headlights run off of the battery. It sounds to me almost like the alternator is running fine but the battery isn't holding a charge correctly, even though it tested fine before i put it on the car and after i drop for 4 blocks with it on. But why would the alternator read at 14 volts off the car in a test and 12 on the car? Am i going to be forced to have it put on a machine to test it and see exactly what is wrong with it?

oh and on top of that, before this happened the batter gauge always read right around 13. When i put the fully charged battery in there it only read at around 10 or 11 even though at the place it was testing good. What could be the problem there?

I agree. If the alternator tests OK on the bench and the battery is good you LIKELY have a bad connection or broken wire. The alternator feild is not getting fed, or there is no connection between the battery and alternator. The second is easiest to test. Put voltmeter on the output terminal of the alternator while connected to the car. You should have battery voltage. If you don't the charge wire is open (most likely a fusible link or a "green" connection) If you do have battery voltage, start the engine and test again. If output terminal voltage goes up, and battery voltage does not, you have a "green connection" somewhere.

A "green connection" is a corroded connection that can allow enough current to flow to indicate voltage on a voltmeter, but not enough to charge a battery or support a load.

If the output voltage stays at battery voltage you have a problem in the field feed circuit, in all likelihood.

ok, got it fixed. Turns out it was something that i didn't even think of. All it was was a fuse under the hood :/ a fuse for the relay of the alternator was blown. that's it lol... glad it works now though