[Mustang02gt]

ok so this year im on my third altenator, one which i replaced last year burned up on me this summer, so i used a spare in my garage that had around 80,000 miles on it , it crapped out about 2 months later i went down to autozone and bought another alternator , cant remember if its new or reman, but i havent driven my car much since ive started working from home, last time i drove my car was saturday and everything was fine, i spent most of sunday in the garage setting up workspace for the 5.4 build and getting parts sorted between whats trash and what can be used, ie trashing head bolts as they will be replaced with new apr head studs, kept timing cover and going to clean it up and get it powder coated or painted. i got in my car to go get dinner today and my battery light stayed on after start up, so i stopped by vato zone and they said my battery was only 45% charged, well the battery was just replaced about 2 -3 months ago after i was at the gas station and it drained due to a result of "cross shorted terminals" i'm wondering if this sounds like my alternator is going bad again or if there's a parasitic draw that i need to look for, where are common areas to find parasitic draws on the 99-04 mustangs, i was thinking it could possibly be my new head unit causing my draw but there's no power going to anything on the car when ignitions off.

i plan on taking the alternator back up to autozone tomorrow and having it tested to double check as it should be a free replacement. if it turns out this is the issue AGAIN can someone recommend a better company for an alternator cause i dont want to be shootin through alternators left and right every 2 months on the 5.4 when its up and running cause i'm sure it'll be a little tighter of a fit to take out the alternator with the blower sitting right above it.

[04MidnightGT]

I've gone through so many alternators... I just bought the one from autozone that has a lifetime warranty and as soon as the battery light starts coming on I bring it in and swap it out. They checked your battery and said it was low because your alternator isnt charging it enough, same thing happened to me.

[Mustang02gt]

he didnt say it was the altenator, though i suspect it is, he started leading me to the idea of me having a parasitic draw which i have yet to have one and havent added much new things that would cause it just to start drawing out of the blew. its acting how my old one did before it crapped out on me . once again just some young kid at autozone that doesnt know much and just fills you with nonsense cause they work for a parts supplier. ill take my altenator up there tomorrow and test it before making them replace it. hope its just the altenator cause i dont want to be tracking down some draw while trying to build a new motor on the side that and want to add HID's soon and a draw would keep me from doing that till i track it down.

[slowgtstang03]

Used to work for autozone. bad thing is, if its not a problem that is going on all the time it could test good there at the store, get home put it on and have nothing.

[Mustang02gt]

im thinking its the altenator, usually battery light doesnt come on for a parasitic draw, if the alternator was working properly then my battery would have been charged completely by the time i reach autozone (about 3 miles from the house with 3 stop lights in between) so by knowing that i would say the alternator isnt charging as it should be , the trip to autozone was made with nothing besides the car running, radio was powered off no plug in the cig. port (car charger etc unplugged) and it was sun down so head lights were on. so my battery being at 45% when i got to autozone i think its not recharging my battery, or the battery isnt holding a charge one the 2

[slowgtstang03]

yes, but if your battery is bad the alternator cant charge it.

[slowgtstang03]

do you have a meter?

[99 blk gt]

I had the same thing happening the light would come one but only when ingave it gas and under load. My volts meter was spiking all the way to the top and shorting out the radio and the lights it was crazy. After the stupid tests they do at auto zone and checking my battery they said it was from a loose connection in my battery. We tighten it down and it's fine for half a day and starts going wack again. This time the volts go to 18 and back to 14.2 so I took it out and brought it inside. They have a bench tester inside which is much better cause they test the 3 parts of the alt which included the regulator the diodes and the ground or something. Well if any fail it's a bad alt. Turns out all mine failed and my battery was fine and just was not getting a proper charge. I went ahead and bought the PA performance alt from American muscle lifetime warranty free shipping and 130 amps for cheaper than what autozone charges for there cheap stuff. Go with PA I have angel eyes halo lights and sequential tails as well as a sub amp and deck. Steeda pulleys and All and I've never had a problem since the 130 amps takes care of it. Get one and forget your worries

[99GT35thLE]

Depending on if you have a big amp in the car you may need a bigger alternator. Also I've seen some heavily modded cars that needed the 200 amp alternator to get them to run properly.

[Mustang02gt]

Originally Posted by slowgtstang03 yes, but if your battery is bad the alternator cant charge it.

but if i had a bad battery then the car wouldnt start without a jump most likely and wouldnt of had a 45% charge when i got to autozone , is this correct? and what type of meter do you speak of? a volt meter?

[Mustang02gt]

ok so i took the altenator out and took it to autozone for them to test it though i already knew the results all 3 test categories failed, who woulda thought ha, i had them replace it but when i was watching them look the part up i noticed they have been selling me a 110 amp alternator, i thought the 4.6 sohc ran a 130 amp ? should this be addressed so i stop going through alternators? i plan on ordering a 130 amp for the 5.4 when its ready .