Crank your steering wheel hard to the left, and turn the truck off. This will lock the wheel in that direction giving you the most visibility. Look at the hub, from behind the wheel. You will see a wire loom running to it. Follow that loom to the front of the truck. It will come to a plug just behind the bumper. This is depicted in one of my pictures. Now, you can either, just pull the plug to disable the abs, or you can split the loom and come to the wiring. To go with the switch, pull one of the 2 wires out, doesn't matter which one. Snip it. Grab some wire. I went with 14 ga. wire. Get some connectors, you can use butt connectors, connect one end of the cut wire to a length of wire running into your interior to the approximate location of where you want to place your switch. Repeat that procedure again for the other end of the cut wire. Put some spade connectors on the end of the wire that you just ran to your interior and connect to the switch. Mount the switch.. You are done. It is not hard. I can literally do this again in about 5 minutes. The hardest part will be choosing a location for the switch. This is all splicing into the wire on the driver's side of the vehicle. All you are doing is breaking the connection. When the switch is on, the connection is closed, allowing normal ABS functions. With the switch off, you are breaking the connection, disabling ABS. Just follow the sensor from the wheel, cut 1 of the wires, and add a switch inline.
Dan