Looking for an under-hood "hot in run" source

[Aaron]

My Dad has a 2004 GM 3500 van (6.0 V8) that he uses for work, and for Christmas I got him a battery disconnect. Basically when voltage falls below 11.7, it automatically disconnects the battery so it won't die. A push button switch inside the cab then re-activates the button and life goes on as normal. No more 0* jump starts at 4:00am.

In order for the thing to work right, it needs a "hot in run" source. I don't feel like taking a wire from inside the cab, and was wondering if there are any under-hood sources. The small wires coming off the alternator should work, right? Are they 12 or 14v? I'd rather not take from the fuel injectors or coils, just don't want to affect engine performance at all.

Thanks!

[The Dark Side of Will]

I'd rather not take from the fuel injectors or coils, just don't want to affect engine performance at all.

You can and you won't.