which vacuum unit do you have on the front axle and you are carb'd right?
i just did the lines on the wife's 93, like an hour ago. when you look at the transfer case switch, there are two tangs that make it so you can't put the rubber plug on it wrong. that port between the two tangs is the one that the vacuum line from your manifold goes to. the one straight across from that port is the one for the vent. the other two are your lines for the front axle. when you have the jeep running and the transfer case is in 2h, the line with vacuum goes on the side of the axle vacuum unit that is nearest the wheel. when you put it in 4h or 4l, the line with vacuum is teh line that goes on the port nearest the differential