Hope this helps
i just went through my FSM and found two power wires for the pcm. a-2 and a-22 .
a-2 is fuse 20 in the PDC and a-22 is fuse 18 in the PDC. also i see that a-22 will have power all the time and a-2 is only 12 volts with the key in the run and start positions. hope that helps some.
94 Grand Cherokee, 4.6 stroker, 7 inch custom long arm kit, 33x12.50x15 Firestone destinations m/ts, flow-master 40 series, magnaflow high flow cat, locked front and rear, super axle kits front and rear, pioneer head unit, CB on channel 10, and a B&M built transmission, switched from a 231 to a 242, 2000 Grand Cherokee steering and knuckles and brakes, no abs, wildwood adjustable proportioning valve, and lots more