Hello Alembic friends!
First time post so please be gentle with me

I am a little confused by the behavior of my Series II Bass and would love to get some input.
I just did a pretty through troubleshooting and found the following to be true:
With NO batteries loaded:
5-pin cable connected, no 1/4": No sound, Have neck LEDs
No 5-pin cable, 1/4" connected: No sound, No neck LEDs
5-pin cable connected, 1/4" cable connected: No sound, Have neck LEDs
With two brand new 9-volt batteries loaded:
5-pin cable connected, no 1/4": No sound, Have neck LEDs
No 5-pin cable, 1/4" connected: Have sound, no neck LEDs
5-pin cable connected, 1/4" cable connected: HAVE sound, Have neck LEDs
Plugging in both cables, I can play to my hearts' content. Well, at least I can try... I'm not sure I've ever reached 'hearts content' while playing before running out of time and having to go take care of something else!

Is the 5-pin cable alone supposed to carry audio from the instrument as well as power to the instrument?
Really long confusing story short: Do I need to send in my 5-pin cable for a check-up? Or is there something I'm not doing that I'm not aware of?
Thanks!
Ben