Put the truck in low ratio or engage the cdl switch. Leave the trans in Neutral turn the Diff Lock switch to the rear position and then jack up one side of the rear axle and the front axle. Turn the rear wheel by hand. If the actuator is working it will engage and you will not be able to turn the wheel any more shoul not be able to turn it as it will be locked to the wheel sitting on the ground.
I have just spent the weekend wheeling in a river and the diff lock indicators flashed all the time even though the lockers were engaging as required. I need to get in and sort out the indicator switches.
Hey Sar, did you resolve your issue with the blinking diff light? I have the same problem, my rear locker engages, I can hear it and feel it, but the light is always blinking.
Any tips would be appreciated.
Thanks