Yes a little more background on what is happening, sounds, lights, things like that. As well as all things checked besides switch would help.
Also year and model you have jarfly. Another thing to try first off is disconnecting the battery. This can reset the 4x4 actuator as it can lose its home position in the ECU. When doing a battery reset you may also experience a high idle on restart. This can be corrected as well be doing a series of restarts. Each restart should lower the RPMs until it starts in normal range.
Dont know if this will help you but maybe it will. I've got a 2012 and had that problem. After tracing everything down I found the problem was where the wiring plugs into the front axle was not plugged in all the way. I simply pushed it down tight and haven't had any trouble since. Also there was no catch or locking notch on the plug in, so I suppose it could come loose again, but it hasn't, been a few years now. Good luck
I have 2012 reeper .the only other problem is temp gauge quit working. I checked the 4x4 switch with a test light when I touch one of the wires it engages the 4x4 when I remove the test light it disengages
If it engages 4x4 did you verify that it is actually engaged or is it just activating the light in the gauge? You can check by having the front wheels off the ground and engaging. With one wheel blocked the other should try to turn the drive shaft. The front is an open diff unless locked. You can also lock the front with the front wheels raised after engaged and it should try to turn the driveshaft. This can be done with the engine off after engagement.
Also when testing with the light how are you grounding? By the other wire or a separate ground?
Then it would seem you have a bad ground. Can start first by making sure all grounds to the frame are clean and made to bare metal. From there it will involve tracing the ground from the switch to locate the issue. Check and clean all connectors on the way.
Also can you provide a picture of your actuator as 2012s had two different ones used depending on your differential. What color is your front differential? Black or silver? This too will help in identifying which you have.