I have a 1999 F250 V10 6.8 l four by four and I can't seem to figure out what is causing the massive drain to my battery. So with a jump it starts right up , but once I disconnect the battery cables it rapidly dies(battery meter quickly goes from middle to dead) so something is killing my battery. I've replaced the solenoid, battery terminals too, but I've got a massive aftermarket stereo system that old owner admitted to not hooking up properly so I'm hoping it's the issue. I need advice! Single mom of 2 and I need my big red truck!!!

 

welcome to this site.
i would start with disconnecting that radio fully, than do a charging system test, your should be getting 14.3 to 14.7 volts out of the alternator ,if not the next move is having a generator shop bench test the alternator , good luck

 

Hey thanks for the reply! Ok so it has a boss stereo in it and there are wires coming up and out from under the dash leading to the back of my truck back seats. My question is where do I begin with disconnecting the damn thing? Ugh hella frustrated!! Thank you in advance! I'm.going to go out to her now and get the exact model of this stereo too.

 

The fact that the engine dies when you pull the jumper cables off means it's most likely the alternator which has failed. Or, the wiring between alternator and battery are corroded, broken, etc.

 

a bad alternator , that's my thoughts also, just having been a dealer mechanic and SM i tend to troubleshoot before throwing on costly non returnable parts ,yes cleaning connectors and grounds is at the top of the troubleshooting list with it being 25 years old there will be many in bad shape

OP' if there are any connections at the battery for that radio start by disconnecting them there