Possibly the rear O2 Sensor? I know on the 95SR the O2 sensors are part of the transmission harness at one point. Here is the 95SR pinout at the junction between the dash harness and the transmission harness...I don't know how it compares to a 93.

Sorry if it's a bit jumbled, I'm still trying to find a good way to post/convert an Excell file.

Connector C-40-3 Dash to Transmission Harness

Pin 1 Yellow/Blue Center Differential Lock Operation Detection Switch
Pin 2 Blue/Orange 4wd Operation Detection Switch
Pin 3 Yellow/White 2wd/4wd Detection Switch
Pin 4 Yellow/Blue 4wd High/Low Detection Switch
Pin 5 Blue/White Center Differential Lock Detection Switch
Pin 6 Park/Neutral Position Switch (Reverse)
Pin 7 White Front O2 Sensor
Pin 8 Black Front O2 Sensor
Pin 9 Black/Red Front & Rear O2 Sensor Shield
Pin 10 Start/SRS Airbag System
Pin 11 A/T Fluid Temperature Sensor
Pin 12 Lock-Up Solenoid
Pin 13 Shift Solenoid #2
Pin 14 Shift Solenoid #1
Pin 15 Pulse Generator
Pin 16 Pulse Generator
Pin 17
Pin 18 Red Rear O2 Sensor
Pin 19 Green Rear O2 Sensor
Pin 20 Brown 0.85 Front O2 Sensor Heater
Pin 21 Black/Red 0.85 Front O2 Sensor Heater
Pin 22
Pin 23
Pin 24
Pin 25 Park/Neutral Position Switch (Low)
Pin 26 Park/Neutral Position Switch (2nd)
Pin 27 Park/Neutral Position Switch (Drive)
Pin 28 Park/Neutral Position Switch (Neutral)
Pin 29 Park/Neutral Position Switch (Park)
Pin 30
Pin 31 Park/Neutral Position Switch
Pin 32 Park/Neutral Position Switch