Exhaustive Diff Lock issue - Nothing has worked. (1 Viewer)

Jul 24, 2017
Hello, I am reaching out to determine why I am having a persistent Diff lock that will not engage. I have a 1997 LX450 with no front or rear lockers. I am on my second transfer case and have had the same problem with my past transfer case, where when switching from H-N-L the truck did not activate the center diff lock. I have since rebuilt the truck and have dropped a used transfer case into the truck that had the center diff actuator stuck in a locked position, complete with ABS light and Center Diff lock light. I know it to be engaged because driving while turning led to squealing tires and I could smell the Oil heating up.

I have followed a great many threads on here and have since tested the relay per the FSM in the driver side kick panel. I have found it to function according to the FSM. I have found the center motor actuator to function according to the FSM and continuity tests. I can hook it as well as the relay up to 9V or 12V and get passing behavior while hooked to a battery, but nothing while hooked and wired into the truck.

I have pulled all of the rolling ball transfer case switches and cycled them, lubed them, and tested them for positive function. I have used the paper clip method to trick my dashboard into believing I was in a locked position and was able to see the locking diff light, but when I shift to L in my transfer case I get zero change in lights. Before I cycled the locking gear with my hands when I had the actuator out I cycled from High to Low and back and got zero change in lights from the locked position.

I have pulled and cleaned the two main transmission and transfer / engine harnesses and I am beginning to believe I have a break somewhere in the line. I have not been able to determine whether or not having a center diff ECU is causing my problem. For some reason my truck doesn't have one, it may be because I do not have a front or rear locker. I have not been able to accurately determine if that is it.

I have not installed a CDL switch or done the 7 pin mod.

my 30A diff fuze is intact.

Can anyone think of something I am missing before I start looking for breaks in wire between every inch imaginable?
Great gratitude and thanks for reading this far.

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