Ok, So in the last year/year and a half I have been working on my 1985 Trans Am. The battery would always die, so I removed the alarm system, replaced the alternator. the electrical in this car isnt the greatest. I have had 2 batteries go bad on me. both have been replaced for free, but I am wondering if there is anything that could be wired up incorrectly that would cause the battery to go bad. not just die, but go bad. yesterday I took the battery to autozone, and they said that after they charged it it would only hold 35% and would drop to 11.1 volts when load was applied. Tomorrow I'm picking up my 3rd battery from carquest, but do you guys think there could be something wired wrong in the car that could be messing up the battery?

thanks in advance

 

I had two constant short scenarios. the first was the main harness shorting against the firewall where it passes thru, it had worn thru the grommet, the second was one of the power door lock buttons sticking in, in the on position. worth checking.

 

well I had taken out the power options harness completely [ power locks, windows, and mirrors] because the previous owner put in an alarm system and wired it into the windows and everything, needless to say I am looking into buying a replacement. And my harness that goes to the engine bay through the fire wall if a block with all the connectors inside, however, I have taken it apart and its pretty dirty in there? I dont see why though, its a sealed plastic box basically.

 

Do you have the battery tie down in place. If the battery is moving around it could slamming around. That can cause the plates to move and will cause them to not function right.

 

I had the same problem it turned out to be a short in my steering wheel horn harness.
To find it I took the negative battery cable off the battery. Put my meter lead one on the negative cable the other on the negative terminal of the battery (in series)my meter registered 12 volts meaning that there was a short somewhere .
To find it I started to pull 1 fuse out at a time until the meter registered 0 volts......keep in mind when doing this to push in your door jamb switch or your meter will register this as your short. When you`ve found which fuse it is.... example radio fuse then you`ll have to trace wires around radio.

 

just was beat to it but it wont be zero.. you will have draws from anything that has a memory like the ecm, radio and so on

 

this is a good thread...gotta connect to it for future reference

 

I had a similar problem and it turned out to be a bad alternator. I was skeptical because I thought if the alternator was bad it wouldn't charge the battery while driving, which mine did. However it was kind of a friend of the family so I said ok and stood there and watched them change the alternator and after that I had no problems. From what he told me if your battery goes dead a lot it is real hard on the alternator to charge the battery real fast. Not sure if this will help but keep it in mind. Oh by the way the reason my battery was originally going dead was because I left my satellite radio on.

 

this is true ...by the way
dont let the battery die when the rear hatch is open
when you have the later version of the hatch motor

 

Well, I do not have any lights in the car [ bulbs have been taken out ]. I dont have a radio, So the only thing that could be draining the battery is a short. I know my alternator is good because I have replaced it. But I was really just trying to figure out if there was anything that could cause the battery to go bad. Not just drain, but actually go bad.

 

With the car running what is your voltage reading at the battery

 

Did you ever solve the problem? I'm dealing with a similar issue.

 

Yes, I had a draw somewhere, couldnt find it myself so i had a garage do it for me =[, and I had some bad grounds.

 

Do you think it could have been the bad grounds? How long did the batterys last, my last one was 3 days till dead unchargeable, nothing. I'm almost scared to put the new one in to start testing things.The store won't exchange them no more. Thanks

 

First thing to do would to test for a draw. If you dont know how to do it or dont have a mltimeter autozone sells them pretty cheap and should be able to easily explain to you how to test for a draw. It could also be a bad alternator or bad voltage regulator.