4hi and 4 low switch lites blinking when selected

[Mikesnewdiesel]

The shift motor seems to change the tranfer case to 4hi or 4lo but doesn't engage front diff. Does the

encoder also tell the actuator to lock front diff? Is the encoder in the transfer shift motor ?

[newdude]

Are you shifting properly in to 4 LO? Transmission in neutral? There is a transfer case control module in the dash that runs the operations. The TCCM is what controls the front differential actuator. Encoder is the transfer case shift motor. If the actuator shits the bed, the front axle won't engage or will be stuck engaged. The diff should be engaged in 4HI and 4 LO. 4 LO puts the t-case in low range.

[Mikesnewdiesel]

yes in neutral . when i put in 4hi or 4 low and put in drive i can feel the truck is in 4 wheel just not the front diff'

The service 4wd message is on

[newdude]

The transfer case module does set codes if you have service 4x4, so if you have a way of getting that scanned that would be a good start before you end up spending $$$ on parts. Seeing that you don't have front axle engagement, the actuator on the axle sounds like a good culprit.