4wd high not working low does.
 

Hey can’t get this 4wd high to work on this 1994 1 ton chevy. Goes into 4 low but not high, has shifter on floor. Replaced actuator on front axle with the upgraded motorized one. Replaced switch on transfer case. Shift to low can hear actuator work and lights on shifter light up. Switch from 2 to 4 high no noise from actuator no light. Is there any other electrical components to the system or am I chasing wires to find broken ones at this point?
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Re: 4wd high not working low does.
 

Since 4Lo and 4Hi are at opposites ends of the shift lever, I would guess that the switch is not engaging properly on the 4Hi end.

The switch could be defective or not installed quite right. I don't know but I sure wouldn't expect there to be a separate wire from the switch to the actuator. I just shimmed mine so the two front axles are locked together all the time.

Re: 4wd high not working low does.
 

I just went through some trouble with my T-case switch. My truck is 1990. I found that the switch is normally closed at rest, so most of the time when the truck is in 2wd, the switch is being activated(pressed) so that it is open. The rare occasion I shift to 4wd, and the switch gets to relax, closing the contacts. I replaced the switch twice. If you check the switch with an ohm meter, it should read closed, or zero ohms with nothing pressing the ball. Now with the ohm meter connected, press the ball it should read open at some point and stay open as you press the ball all the way. The first switch I purchased read closed, open, closed before I installed it, after it failed it was just open. The second one, I brought the ohm meter to the store and tested before buying. I tried to find information about what surface inside the Tcase that makes contact with the switch, but I couldn’t see from several exploded images, so I don’t know if that could affect operation. As a last ditch solution, you could wire a toggle switch to replace the Tcase switch. Attached schematic is for 88 to 9?.

Re: 4wd high not working low does.
 

An advantage to that solution is that then you have a 2wd low range option :)