Hyundai Terracan no 4x4

4X4 just stopped working. As I am in Cost Rica, I've waited nearly a year for the new switch---which my mechanic said was the problem. Then I found another Terracan, borrowed the switch, & still not working. Removed the drivers' seat & the 4X4 computer & cleaned it up. The 4X4 & 4X4 Low lights come on when I am holding the computer in my hand, & go out when I ground the computer. Turning the switch between 2 4HIGH & 4 LOW does nothing. Any ideas appreciated.