Yep, as has been said. The solenoid just needs power going to it. I used my 4WD controll switch to control the locker switch... simple logic, it can only provide power to the OTRATTW switch when it is in 4lo by tapping the output of the mode switch in 4lo. Do, you don't need the diff lock control module. I'm trying to remember if I even bothered with a relay. It doesn't pass any current really, just provides voltage to the solenoid to actuate it. I may have, I just don't remember right now. I do remember testing the locking solenoid with a 9V battery and it worked, there really isn't a lot of draw on it.... but knowing myself, I probably did use a relay for fear of drawing too many milliamps off of the 4WD mode switch.
The other two leads are the diff lock position switch. When the diff is locked, it provides contact and you have continuity on the two leads... one lead should go to a ground somwhere, the other lead should be the ground leg off of a light on your dash... So diff is locked, switch contacts close, you have ground, and the light on the dash lights up and you've got an indicator. Kneebuster has a writeup of getting his indicator to work in the instrument cluster. That didn't work for me because mine is an SE model which has a different instrument cluster. I tried it and it didn't work, and I haven't gone back and tried to rework it since then, doing without an indicator light. What I'm going to do is use that ground path from the diff lock position switch on the light on the OTRATTW switch, so when I flip the switch to on, the light on the switch won't light up unless the diff is locked, and that'll be all the indicator I need.
PS, sorry I didn't get back to you sooner OZ, I'm in the midst of some marital strife that has me moved out of the house and shopping for a lawyer right now...
