The lights flash from the Active-Trac ECU that's monitoring the various switches which are inputs to it. If the front slider switch which shows that the front diff is engaged/ or not engaged is acting up, then the ECU isn't happy. Usually the lower set of lights which show 2-wheel drive burn out over time since they're always being run by the ECU, and you just need 2 new bulbs. If the previous owner hasn't engaged the front axle for 4-wheel drive in awhile, the system DOES seem to get a bit temperamental. If you could have spent more time with the Montero, working the system through its places/ranges, it might have calmed down after awhile. Loose vacuum hoses for the vacuum motor at the front diff and for the vacuum solenoids that run this system can act up too.
Someone had popped the main feed hose off the top vacuum solenoid on mine when I first started to look at it. Reattached the hose by the left valve cover, worked the system in and out of 4-wheel High for a few days in the winter, and all was well.
I DO seem to have the best and fastest engagement of the system by going straight into 4-wheel High or Low center diff lock with the truck standing still and in neutral, then going back to 4-wheel High once the front axle slider has moved over into place if I only want that range and the T-box diff unlocked.
Running the vehicle at higher speeds well under the engagement limit[62mph?] and trying to get it into 4-wheel High with me letting off the accelerator pedal hasn't worked like the manual states. <img border="0" title="" alt="[Embarrassed]" src="images/icons/blush.gif" /> <img border="0" title="" alt="[Embarrassed]" src="images/icons/blush.gif" /> <img border="0" title="" alt="[Embarrassed]" src="images/icons/blush.gif" /> I still have better luck at a standstill. Besides, I'm a little nervous having that diff engage with the spinning parts at higher mph's anyway. I know Mitsu states it's made for it with the shift-on-the-fly, but they're not buying me any parts if something goes wrong. <img border="0" title="" alt="[Razz]" src="images/icons/tongue.gif" /> <img border="0" title="" alt="[Razz]" src="images/icons/tongue.gif" /> <img border="0" title="" alt="[Razz]" src="images/icons/tongue.gif" /> Houston