Bypassing Vac system

Hello ☺️

First post here, if i have posted in the wrong section please move it or if someone could point me in the right direction i would greatly appreciate it.

So, bought (unwittingly) a 2007 gen 3 with a whole host of problems, however rather than sending the vehicle to the great scrapyard in the sky i am saving her. 

Slowly getting jobs done but have got to the 4wd system. Green 4h light constant flashing, buttons dont seem do anything. Rather than invest a small fortune replacing the vac system i intend on instaling manual hubs. A while ago i found some info on bridging/joining two wires to fool the system but cant seem to find it now. 

Any help please? 

If you look underneath the battery there are a side by side pair of electrically controlled valves with a nest of rubber pipes that control the hubs.
There is also a round switch attached to one pipe.

Join the wires that go to the switch.

The 4WD controller will think that the hubs are working. (Strictly it will think that there is no vacuum leak and assume that the hubs engaged)

Replacing the whole vacuum system with new PVC hoses costs about £15 and is a quick and easy job to do. But before you do anything you need to make sure you're fixing the correct part. Do as Facade says, bridging the wires in the white plug. If this fixes it then replace the hoses. If you still have issues with the plug bridged there's a very good chance it's a problem with the transfer case, typically the actuator. So check this is working before you spend any money.