I had a question on the operation of 4wheel low in my Lexus LX-450. The shifter will go into low but I get no Diff Lock indication on the instrument panel. I believe that this should automatically happen in low. I do see the A/TP momentarily light when in park or N as I shift from H to L. The gearing seems to “lug down” as if something has shifted in the center differential but I get no indication that all wheels are pullin together as when they are locked. I know that this worked years ago but I have never needed or exercised this option recently. Would this bea center differential lock switch, motor or solenoid? I’m not sure if there’s a fuse in the system for the solenoid. I heard that there is a mod that can be installed with a CDL switch in the dash along with a pin 7 mod. I currently do not have these installed yet. I am kind of new to this so any advice would be greatly appreciated. Thanks.