BLK/YEL, BLK/WHT, BLK/RED, BLU, BLK)

I don't know what year your truck is, but from the 89 factory shop manual (go to your home page and edit you sig line to show your truck model for future quicker and more accurate help). I'll list the actual wire color, followed by the stripe color if any and a preceding number that is the cross sectional area of the wire conductor expressed in square MM's, the bigger the #, the fatter the wire. 3 is about 1/8" diameter copper conductor.

fat white wire (3W) 12v+ from battery, via 100A fuse, and fusible link marked ign-st

Black/Yellow (2BY) Ign start position power out to truck to starter solenoid and any other users that take ign start power, like the FI control relay.

Black/White (2BW) Ign on position power out to truck uses

Blue/White (2LW) Ign accesory position power out to truck

Black/Red (?BR) not shown on any shop manual I have for the ign switch, but the fi wiring diagram shows one for the power to the fi relay, which turns on the ecu and fuel pump. black/red is usually a constant on 12v wire in the mitsu scheme of wiring colors, but not always.

Black - probably a ground wire but should not go to ign switch.

Look up any post by montymcv and there'll be a link at the bottom to his site from which you can download an electronic copy of the factory shop manual. A must have...