Hi, I just found this sight. I am wondering if anybody can help with my 4wd. Here is the story. 93 s15 jimmy push button 4wd. When I push the button, nothing happens, no blinking lights, nothing. If i am in revearse, the lights will blink, but it doesn't go into 4wd. I replaced the switch at the transfer case. Nothing changed. Found a hole in the vacuum tube by the actuator under the battery. Replaced it and the 4wd worked great. It would go in and out like it is supposed to. A few hours later, I got in the truck again and it is doing the same thing as before. Anybody have any other ideas besides a lot of gasoline and a match??????????