I have a 1999 which has the four button 4x4. Once and awhile it works just fine. 2HI button stays lit. Switches into 4HI without a problem. But then, for seemingly no reason, all the lights on the switch will flash. If I'm lucky at that point, the Service 4x4 light on the dash will blink and after some clicking down by the passenger door, the 2HI light will come back and the rest of the lights stay off. If I am unlucky, after the flashing, all the lights for the push button will just stay off and I have nothing. Any ideas of where to start looking with this issue? Thanks!