Rear Differential Lock Circuit (With Differential Lock)
- Start engine. Ensure rear differential indicator light illuminates when top of rear differential lock switch, (located below radio) is pushed. If indicator light illuminates, go to next step. If indicator light does not illuminate, turn engine off. Check wiring harness between rear differential lock control unit and rear differential lock switch. Check rear differential lock control unit power circuit. See REAR DIFFERENTIAL CONTROL UNIT . If circuit is okay, replace rear differential lock control unit.
- Disconnect ECU connector. Turn ignition on. Using DVOM, check voltage between terminal No. 108 and vehicle ground. See Figure . When rear differential is locked, battery voltage should not be present. When rear differential is unlocked, battery voltage should be present. If voltage is as described, substitute ECU with known good unit and retest. If voltage is not as described, repair wiring harness between ECU and rear differential lock switch.