I have a 04 F150 new body style, and the 4x4 will not engage. I recently had a rachiting sound in the front and the the 4x4 quit. I was told to change the switch under the hood on passenger side on the fire wall. Not sure of the tech name but from what i understand it send the vacume to the axle. It didn't change anything so my next step was to change the actuators at the wheels or axle seals whatever there called. The 4x4 still wont engage. The light comes on but no 4x4. I also blew all the lines clean while it was apart. PLEASE ANY INFO WOULD BE GREATLY APPRECIATED!!!!!!!!!

 

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