Rear diff lock not engaging

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Oct 11, 2010
Calgary, Canada
Hello all,

Posting here because I get no response from the 100 Series side and the similarities of the 80/100 system
Vehicle is a 98 LX470 with factory rear locker
Rear diff actuator is the same as any locked 80
Dash switch is the same with the exception of the FR position

Current issue is that I'm getting only 8.43V at the rear locker actuator and I'm guessing is not enough for it to operate.
- Rear actuator was bench tested cleaned and greased by reputable shop in Edmonton.
- Famous wiring harness from actuator & rear ABS sensors over the frame to main body harness was replaced with new OEM
- Connector from body harness to new rear diff lock harness also getting 8.43V
- Center diff lock operates perfect in HI & L
- OEM locker switch is also New
- When hitting the rear locker switch, ABS light goes on, rear diff lock blinks and the relay clicks on the passenger side area
- Diff lock fuse under the divers side kick panel fusebox is also good
- Like the 80, the 100 has to be in low range with the center locked in order to operate the rear locker

I'm not sure what to check next
Where is the next connector (back to front) that I can measure Voltage?
What voltage I should be getting at the actuator plug?
My next thought was to check voltage at the ECU but unsure how to due that is only one plug coming into it
Looking at this diagrams from the 80 Series it seems that 3 wires come into the ECU and 4 come out. If I understand this correctly, I should get from 9V-14V coming out of the ECU towards the lock actuator in order for it to work?



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