My 2001 f150 4wd, is having some 4wd issues. The 4wd did not work when I got the truck, the 4wd light came on in the cluster but that was about it. I replaced the 4wd engage switch on the firewall, and it seemed to engage ok, it would usually have to be driving at a steady speed for it to come on, it would never engage in park or at low speeds ( this is my first ford truck so I don't really know how there 4wd systems are sopouse to engage). Now I have no 4wd again, I have lights on the dash and vacuum on the blue vacuum hose off the solenoid on the firewall to the front diff actuator when on. Not sure where to go next any help would be greatly appriceated. Thanks

 

Is the actuator moving?

 

I haven't been able to check that yet the front shaft is spinning when in 4wd, you can move the actuator manually but I will have to wait till tommrow to check operation of the actuator