I'm finally getting started on my stereo system and need to know which of the 2 underhood batteries is the "aux" battery so I don't wire all my junk to the one dedicated to the starter.

Thanks!!

Don

I know a few guys have used that box that is there for jumper cables to wire up amps and other various high current electrical devices. I'm pretty sure that the batteries are used together to start the truck up, reason for this is that it takes a lot more juice to fire the diesel than a regular gas motor because of the glow plugs, intake heater, fuel heater, and a huge starter to crank the high compression motor. Long story short i don't think it matters which battery you hook up to.

Connect to the Little red box, cleaner install, easier battery removal/replacement if you every need to, and then as a plus, your dealer will like you alot more.

I'm finally getting started on my stereo system and need to know which of the 2 underhood batteries is the "aux" battery so I don't wire all my junk to the one dedicated to the starter.
It doesn't matter much on the Duramax. The batteries are wired in parallel. But the red jumper box is probably cleaner and easier.

Jim

Ok, good stuff, looks like I'll just use the jumper box. I just remember that on some of the older GM trucks, one battery would be an "accessory" battery and the other dedicated to the starter.

If you have a hi juice requirement for subs and such, (if your amp is fused over 50 amps) you will want to hook up directly to the battery, preferably an optima. And use 8 gauge minimum. This will help the amp get the need juice spikes for good LF reproduction. A common error is wiring that starves the amp.

I know you didn't ask for stereo advice, but if you like running it when the truck is off, consider a link that isolates one battery from the other during discharge, so you can still start after running one dead.