Okay, I have spent several hours researching on this forum and other the front wheels flashing while in 2wd. I understand the blinking indicates the vehicle is attempting to engage 4wd. The common themes addressed are the vacuum lines, the freewheel clutch solenoid and freewheel clutch switch. I have looked at the vacuum lines and they are all soft and not cracked or dry rotted. Which leaves me between the solenoid and the switch.

My questions - what experiences have others had? Which is more likely the problem? Can the either be cleaned/lubricated to restore function? I saw one post about engaging and disengaging repeatedly freeing the system up, but and skeptical since I have done this many times trying to discern what is doing on with mine.

2002 Montero XLS 101K miles

 

The lights will flash when you go from 2wd to 4wd, or from 4wd to 2wd. Have you tried engaging 4wd? Will it go in or not? If it does go into 4wd and lights stay ON, will the vehicle go out of 4wd into 2wd or that is when the light keep flashing? If the lights keep flashing when you attempt to disengage 4wd, that can indicate the sensor on front axle is malfunctioning or there is some binding up going on that is not releasing.

 

Yes, HunterD. While 4wd is selected the front wheels engage, all four wheels pull, and the front wheel lights are on and not flashing. While in 2wd, the front wheels do not pull and the front wheel lights flash. The impression I had from my research was this indicated a freewheel switch or solenoid, which I assumed was like an automatic hub lock. I have not read anything about a sensor on the front axle.

 

It sounds like the actuator on front axle is not disengaging fully when you shift into 2wd. I doubt it is the solenoid. It is more likely the switch. It can be as simple as bad wiring (open or grounded circuit). I'd check that first. Another possibility is some grime or debris are preventing full range of motion on the actuator and it is not able to travel full range and thus not activating the switch. I'd check two of these possibilities first and proceed further if indicated.