I'd like to apologize for this long post, but I really need help in trying to figure this out. I've searched to no avail.

Recently installed a Blitz turbo timer with a harness on my STi using these instructions (for enabling the factory alarm system while the turbo timer is running), and my ABS is now staying on immediately after the install.

Instructions I got from Mach V Motorsports:
Step 1: After installing your turbo timer with the under dash panel off, locate the black relay box on top of the fuse panel. Unbolt 1 (10mm) bolt and cut the Green with Black wire. Tape both ends of the wire and reinstall relay box. Reassemble under dash panel.

Step 2: Remove the panel in front of the armrest by pulling up on the cup holder. Disconnect the power mirror terminal. Locate the wiring terminal for the security system. Cut the Grey Wire. Tape both ends. Reattach power mirror terminal and cup holder panel. Enjoy!

The green wire with the black stripe under the dash leads to the keyless entry relay box, so I doubt that could be the cause. When I pulled the panel with the cup holder out and looked for the gray wire, there were two of them. Thick ones. I checked to see where they led to. One of them led to a harness that wasn't connected to anything. The other one led to a sensor near the back next to the arm rest, with a stamp on it that says "do not disassemble." Since the second gray wire I checked was connected to the sensor, I figured that would be the one, and cut it. Put everything back together and started the car to test the turbo timer, and to see if my alarm would arm with the car still running. It armed, but now the ABS light stayed on. I tried reconnecting the gray wire, but the ABS light still stays on.

Any idea what the cause would be? What exactly is that sensor for? Any help would be appreciated. Thanks in advance.