4WD engagement questions

I have realized the front end is not locking in again. I checked the system out when I first got the truck back and found it not operating. I swapped the hoses at the vacuum solenoids and it worked for a little while while all fours were in the air. Then it disengaged. I swapped the solenoids hoses back and it began working and releasing just fine. Now it will not engage again without swapping the hoses. I am not getting the 4WD light to come on either now. I verified the switch in the differential is giving continuity when locked in. I also confirmed that the vacuum solenoids no not change electrical command when in or out of 4WD with the transfer case shifter. The solenoid to pull the differential to lock in never gets commanded to change and allow vacuum through.

Is there a good drawing somewhere here to help me troubleshoot this system? I thinking and hoping there is.


Thanks in advance for any and all help,
Michael