4x4 problems
Looks like you have the ESOF. The hubs lock and unlock via vacuum. Sometimes due to bad bearings/seals the hubs will not lock and if they do they won't unlock. Sometimes the hubs are bad and won't lock/unlock. Disconnecting the vacuum lines won't help one way or the other. One pull of vacuum locks them and they stay locked until another pull of vacuum unlocks them. There is no constant pull of vacuum on the hubs, in other words.
First of all make sure the switch on the dash is set at 2WD and that both hubs are in the AUTO position. Then turn your tires hard right. This way you can turn the front driveshaft by hand and see if one or the other axle shafts turn. The front diff is open and the front driveshaft should turn freely if just one hub is bad. If the driver's side axle shaft is turning, then that means that passenger's side hub is not functioning properly. If the front driveshaft does not spin at all, both hubs are still locked. In that case you may not be getting sufficient vacuum to unlock them.
Take your time and determine where the problem is. Again, make sure that both hubs are in the AUTO position.
Sufficient info on your truck and good feedback is a must at times like this.
Spill your beans.


