I have a 91 wrangler and its 4wd vacuum lines had been broken when I 'inhereted' it. I decided to reconstruct the lines with the help of the manual.
I realized that I do not have the Command-Trac shift motor pictured in Chilton's. The one in the manual has 3 vacuum ports, front port (which is the one away from the pointy thing), rear port and 4wd indicator lamp switch port. Mine has only two ports, front and back. So I can not follow the connection schematics there.
I reconstructed the vacuum lines, with guessing and using the traces of whatever is left. There is a T on the vacuum port at the intake manifold. One port of the T goes to the indicator lamp, and the other port goes to a filter like thing then to the transfer case. On the transfer case there is a plastic plug with 4 vacuum lines attached ( properly called a vacuum harness?)of the 3 remaining lines one goes to a filter like thing and ends there, and the two goes to the motor. I connected the line with vacuum on to the rear port of the motor and the last one to the front port of the motor.
The main problem is the 4wd light is always on. However I can switch in and out of 4wd with a clicking sound coming from the transfer case, I test with turns and I feel it.
My guess is that 4wd indicator light should have a connection to the transfer case or motor, not directly to the manifold.
Is there anyone who knows the exact connection scheme for this type of motor and on what principles the indicator light works (should there be vacuum or not on the light line)?
PS: I read the other posts in this group on this matter and some people mention color coded vacuum lines. All the lines on my car are black, I am not sure if this means it is an earlier model or the lines are not original.