I think I messed up big time.
I was installing a sub and for the remote turn-on I spliced it into the green connector in the back of the HU. I spliced into the A2 wire (the purple wire next to the red wire). Here is a link to see the pin layout:
http://theeshadow.com/files/volvo/aum2.pdf

This worked great, BUT on the amp the REM connection is located between the +BATT and GND connection. the REM wire touched one of the two while on (I think the ground) and sparked. When this happened, the HU shut off immediately and won't turn back on..
I checked the two audio fuses in the dash and they're good. I have the USA-SPEC (iPod interface) and it still gets power.

Did I completely fry my HU?
Please help

 

Found the issue. After closer investigation i realized there is another fuse location a little more hidden, under the steering wheel column, where a fuse was blown. I replaced it and problem solved!