You need the Genuine GM service manual for your model year and vehicle type. ('93, C/K?)
Follow the instructions for diagnosing Code 24.
Wild Guess: Not a ground problem. Perhaps broken wire(s) or cracked insulation on the VSS wire harness.
When that was my '88, it was a faulty instrument cluster. But I'm not sure the '93 uses the same VSS system as my '88. I'd lose the speedo, odo, cruise, ABS, and torque converter clutch all at the same time. A few miles--or days--later, it would "heal" for awhile. Totally random, totally unpredictable.