Where's the Impreza relay block?
 

I'm installing seat heaters in my wife's 2001 Impreza, and wanted to hook them up using the rear accessory outlet wiring, which we're probably never gonna use. The wire comes out of the rear accessory relay, which is located in the relay block under the dash.

According to the service manual I've got, the relay block is under the dash somewhere around the steering wheel, but I can't find the sucker. It's got receptacles for 7 relays on it, so it must be pretty big, but it's eluded me so far.

Anybody know where it might actually be, or can anyone offer a suitable alternative? I need a switched source so the battery doesn't run down if the seats are left on, and I don't really want to use the front cigarette lighter wiring because we use that for other things.

Thanks in advance.