I have a 92 F150 with aftermarket manual locking hubs (warn). The 4x4 is I engaged via push-button. However, when I push the 4x4 button, nothing happens. No lights come on. There is no click, no sound, nothing. I was wondering what the problem possibilities were. Do I need a new transfer case actuator? New 4x4 button switch? Please feel free to give your opinion.

 

Most likely it's the electric shift motor on the t-case or the attached gearbox, disconnect it from the t-case and try to shift it with a wrench and also see if the electric motor works.