stevennc

I am really having a hard time getting my car to start charging again. Basically one day had my brake and charge light pop up. Brought my alt to napa and had them check the alt. It never made it passed the light cycle test or what ever the first test is. Ended up buying a Autozone reman that tested positive on their machine and brought it home. Installed it and I'm back at were I was before still no charge. Checked at the posts and im just getting lower and lower on voltage. Checked the 80amp fuse and it seems fine. Previous owner put in a multi battery isolator...can that fail?

PowerstrokeJoe

I'd take the alternator in and have it tested. It wouldn't be the first time one was bad out of the box.

scope103

stevennc did say that the Autozone reman "tested positive on their machine." I presume that means right before he took it home.

Sure, why not? I'm not familiar with whatever you have, but the purpose of an isolator generally is to disconnect batteries in sequence. Do you still have multiple batteries? If you check the voltage on each one while running, is one at ~14.1v and the others at ~12.6v? If you now only have one battery, could the isolator be trying to charge the "missing" battery?

TNRabbit

You first mistake was trading in that fine Denso stock alt. on a crappy NAPA.

You could have probably replaced the brushes (less than $10) & had a perfectly good alternator.

Take it back, see if they have your old one, then get replacement brushes & re-install.

stevennc

The first thing I did was re install new brushes before anything else. It didn't solve the problem so I took it into napa and the alt failed the light cirquit test (I believe that's what its called) basically the first test. That's what made me get the autozone one..

There is no second battery, and hasn't been since 2007 when I bought it. I will check the rear second batt leads when I get home to see if they are getting a over 14 v. Maybe
A new isolator can help too

stevennc

could the 80 amp alternator fuse show connectivity but not function

scope103

I wouldn't pull the isolator on a whim, but if you think that's the problem, do you need it? If you only have one battery, getting a new isolator doesn't make much sense to me.

One thing's for sure: you may have to wait a while before someone on this forum (who knows your isolator) comes along and can help.

stevennc

Ok tested the leads for the missing second battery. They are charging at around 14. So now I think i can pin this down to a wiring issue or isolator issue. Both headlights work but are dim due to being on batt power. switching both pos leads on the isolator to see what happens

stevennc

switching the positive leads on the isolator gave me charge to the battery. It is a sure 9523a. the #1 pos lead im guessing is shot now, so replacing the unit for 30 eventually would put everything back in line, and leave me with the option of running a 2nd battery in the back still and possibly run my amps off it in the future. Now I am having alarm issues. Its never ending.


This has been a pain and im guessing my denso alternator sitting at autozone is still fine.