Here is a copy of my notes:

Solenoids.
4x4 Solenoids are on the firewall behind the battery.
The 4x4 engage solenoid is closest to the fender. Red ground wire.
The 4x2 engage solenoid is closest to the engine. Gray with black striped ground wire
The bottom nipples receive vacuum from the 4x4 vacuum reservoir.
The top nipples feed vacuum to the Actuator motor on the front axle.
The white line feeds vacuum to the 4x4 engage solenoid.
The black line feeds vacuum to the 4x2 engage solenoid.
The blue line from the 4x4 engage solenoid feeds vacuum to the actuator motor outboard port to engage the lockup collar.
The red line feeds vacuum from the 4x2 engage solenoid to the actuator motor inboard port to disengage the lockup collar.
In 4x2 you should have vacuum on the top nipple of the 4x2 engage solenoid.
In 4x4 you should have vacuum on the top nipple of the 4x4 engage solenoid.



When activated the solenoids route vacuum from the bottom nipple to the top nipple.
When deactivated the bottom nipple is sealed and the top nipple is vented to atmosphere.

 

So since my 4x4 low light comes on, does that mean its engaging? And that that solenoid is good? My 4x4 light doesnt come on only low...

 

Get a vacuum gage and check for vacuum.