emergency start has been hardwired?

Your batteries positive sides are joined together with a solenoid. Open your hood, it may be to your left. The two large contacts come from the positive side of each battery. The small wire comes from the emergency switch. Note the color of the wire, and see if you can find it under the dash. If it is shorted to another wire under the dash, separate it. One of the wires goes to one side of the missing switch, the other wire goes to the other side of the switch. If you can't find the wires under the dash, just disconnect the small wire at the solenoid. Then run a new wire to the missing switch area. Install a switch with one contact going to the small wire you just installed. Connect the other side of the switch to the positive side of the house battery at the fuse box.