Where can I find a diagram of all the plugs and basically the rear view of the Shaker 500 head unit?

 

Shaker 500 Pics on Ebay

Plug 290A

Plugs 290B & 290D

 

Interesting, I wonder what subwoofer high vs subwoofer low means...

 

Door sub outs and rear sub outs. Pre-amp level.

 

What does plug 290A do?

 

That is the CAN BUS that allows for auxiliary in, and it also allows the car's computer to access info to and from the head unit. It isn't very sophisticated in our cars (thankfully), but it will be used more and more in the future. Go read some at VWVortex about their head units starting mid-2002. That's what ours will be soon.

EDIT: I think it also controls illumination functions in our cars.

 

Okay, so I see what's required as far as harnesses and connections. However, obviously, the aftermarket radio won't be using the CAN bus... what role in our cars does the CAN bus play specifically? Is it cool just to leave it unplugged?