Gauges,door locks, windows, ac module not working

Have a 91 chev Silverado 5.7 liter 5 speed manual. My son was driving today and door locks,windows, ac module and guages ( except speedometer and tach) all quit. Signal lights are on solid. I pulled each fuse until I could got signals to go out. Courtesy fuse is one that turned them off. I checked with vom and I have short to ground, also checked with power probe showing 4 volts on ground side with fuse in. Switch off. Power probe shows no short to ground with fuse out. I have tested all bulbs and switches for doors. I am wondering if I possibly have bad ignition switch since I am getting voltage with key off? Thanks for any help.

Have a 91 chev Silverado 5.7 liter 5 speed manual. My son was driving today and door locks,windows, ac module and guages ( except speedometer and tach) all quit. Signal lights are on solid. I pulled each fuse until I could got signals to go out. Courtesy fuse is one that turned them off. I checked with vom and I have short to ground, also checked with power probe showing 4 volts on ground side with fuse in. Switch off. Power probe shows no short to ground with fuse out. I have tested all bulbs and switches for doors. I am wondering if I possibly have bad ignition switch since I am getting voltage with key off? Thanks for any help.

the ignition switch is not part of the door locks circuit. a bad corroded or missing ground can cause all these different failures because a ground is the common on these ,not the source . being this old I would disconnect the battery then start removing grounds and cleaning them .. move them is the metal is gone. fuse box remove and check under the box that the wires are in good shape. make sure the fuses sit tight in the fuse holders. check wires for fuse able links that corrode these wold be the larger diameter wires of a heavy gauge,