battery light help

ok i have the weirdest thing going on right now. So yesterday driving home my battery light starts to flicker, so when i get home i test the battery and the alternator and im on getting 12 volt out of each when the truck is running. So i get a new alternator put that in and now my battery light is on and i'm still getting 12volts at the battery (and yes i did charge the battery last night). So i test the alternator with the truck running and i'm getting like 18 to 20 volts (normal i think). So then i replace the battery and it still keeps doing the same thing. The battery light is on and all i'm getting is 12volts at the battery with the truck running. The odd thing is when the truck is just idling the light flickers but if i give it any gas or put a load on it the light stays on.

 

Did you charge the battery before sticking it in the truck?

 

18 to 20 is a bit high said in manuel that I have if I remember was 13.5+\- 5%

 

High voltage from the alternator is USUALLY (but not 100%) a result of a bad connection, or a bad ground. Check the battery terminals for problems (loose, corrosion, etc) as well as the connection to the fuse panel from the battery, and the battery connection at the alternator. Also inspect the ground cable to the engine block, and the body. Then, if all of that is good, check the alternator mounting and make sure the bolts are clean (no oil or dirt or corrosion) and that they are tight.

 

thanks i'll check it out tomorrow, i was figuring at this point its got to be a ground or something like that. I mean i did clean up the battery terminals, and the alternator wire, but i'll chase some grounds tomorrow.

 

It is also possible that your new (rebuilt, I assume) has a bad regulator.
13.8-14.6 volts output is normal.

 

I get 14.3v.

Output should sty around 13ish


18 is way to high. That will fry stuff. Make sure alt fuse is still good.

A good autparts place can test alt.

 

ok update. Got a second new alternator today and put it in and i'm getting all the right voltage from everything and the light went out. Guess the first alternator was bad.

 

Geez, I hate being the Quality Control person for something that was just "remanufactured". Happens all too often.

 

Out of curiosity, what company remanufactured the bad alternator?

 

^^ THIS I gotta know.

 

Dunno about op. I'm on 4th reman vatozone unit in 3yrs

 

Buy once, cry once.

There's a reason I'll pay 50-75% more to buy from Toyota.

 

Its the lifetime warranty man. Keeps pulling me back. Yeah Togo is the way tobgo on 80% of stuff.

 

Lifetime warranty doesn't help me when I'm wearing slacks, a polo, and my wingtips and the truck dies 30 miles from home at 5am on the way to work.

 

I was joking.

 

A lot of guys aren't... they just get "free" pads and balljoints from Vatozone forever.

I don't mind working on my vehicles, but I'd rather be modding them than repairing them

 

ha ha ha they both came from carquest, the first one was some no name brand made in mexico, the second on was a Denso, that i was lucky enough to get for the same price as the crap box first one, (thank god for being friends with the guy at the parts store)

 

This is why I rebuilt my own alternator rather than swapping in a new one. Only took me about 30min to rebuild it too.

 

Joey, when you rebuild, what do you normally replace besides the brushes?