Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Rear Differential Control Unit
Remove rear seat and remove rear differential control unit. Do not disconnect control unit harness connector. Backprobe harness connector. Check voltage between each individual terminal and ground terminal No. 6 (Black wire). See Fig 1 and REAR DIFFERENTIAL CONTROL UNIT PIN VOLTAGE CHART . If after all tests have been completed system is not operating properly, substitute rear differential control unit with known good-unit and retest.
| Terminal ID (Wire Color) | Function/Description | Voltage Value (DC Volts Unless Otherwise Specified) |
|---|---|---|
| 1 (Blue/Red) | Rear Differential Lock Switch (OFF) | KOEO - Battery Voltage With Transfer In "N" |
| 2 (Yellow/White) | Vehicle Speed Sensor | KOER - 5 Volts With Wheels Rotating |
| 3 (Blue/Yellow) | Ignition Switch (IG1) | Ignition Off - 0 Volt |
| 3 (Blue/Yellow) | Ignition Switch (IG1) | Ignition On - Battery Voltage |
| 4 (Red) | Rear Differential Lock Air Pump | KOEO - Battery Voltage When Pumping Air |
| 4 (Red) | Rear Differential Lock Air Pump | KOEO - 0 Volt When Releasing Air |
| 5 (Blue/White) | Center Differential Lock Switch | KOEO - Battery Voltage With Transfer Unlocked |
| 5 (Blue/White) | Center Differential Lock Switch | KOEO - 0 Volt With Transfer Locked |
| 8 (Red/Blue) | Rear Differential Lock Detection Switch | KOEO - Bat. Voltage/ Differential Unlocked |
| 8 (Red/Blue) | Rear Differential Lock Detection Switch | KOEO - 0 Volt With Differential Locked |
| 9 (Blue/Yellow) | Rear Differential Lock Switch (ON) | KOEO - 0 Volt |
| 10 (Red/Yellow) | Rear Differential Lock Indicator Light | KOEO - 0 Volt With Differential Locked |
| 10 (Red/Yellow) | Rear Differential Lock Indicator Light | KOEO - Battery Voltage With Differential Locked |
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.