1997 Chevy Truck

I installed a performance chip to the back side of my OBII port and believe that I shorted out the power wire as now I have no power to the OBII. I use a scan gauge to check my engine performance and now there is no power to this scan gauge. I hooked the scan gauge to another vehicle and it works fine. I have a repair manual but it doesn't have any electrical schematics that I can trace out the wiring. Is there a fuse or component (I hope not the computer) that I have blown and can replace? I have checked with a chevy dealership and they want an astronomical amount for a electrical schematic.