Other day driving. Saw volt meter drop gradually. Then all gauges flatlined. It has a new alternator and a new yellow top battery that tested good. When the battery was installed in the truck, when I started it the volts on the battery dropped from 12.5 to under 6 by just starting the truck. Any recommendations? Or any solutions?

 

Forgot to say that the whole reason that I put the new alternator on was because my battery light kept flashing. So I was told it was my alternator.

 

brand new or reman alt? What's your voltage reading with the truck off on the bat? What's the voltage reading with the truck running at the bat (anything above 13 volts is ok, low but ok.. ideal is 14+ volts)?

It could be that your alt. decided to die on you very early, or your battery could have a bad cell (got one like that once... pain in the butt to troubleshoot... "just replaced the battery.. that can't be it).

If that gauge dropped like that, then neither your alt was working (you should be able to remove the battery cables and still have the truck run if your alt is working right) and your battery was dead and going deader. Take the battery out and have it load tested at a battery shop (much different than when you are just connecting to it with a multi-meter).

Check the connections on the alt. Check your vehicular grounds as well.

 

Corroded cable may be the cuplrit. As mentioned above, check grounds and all connections. You need a solid clean ground.

 

I just got the battery and the alternator back from autozone and they said they both tested good. I have heard not to go to them so I am wondering if I should take them somewhere else. I believe that the alternator was new when I bought it and they tested it right there before they gave it to me. One thing that it is doing is when the truck wont start and only the solenoid on the firewall will pop a few times. But then as soon as I juice the battery by jumping it the truck fires right up. But gradually the voltage meter begins to drop slowly. Usually takes 5 minutes or so for the battery to go from 12-13 volts to 5-6.