First off I am limited to what I can do due to being disabled. Worked on vehicles for 23 years, but now I don't have the resources that I once had. 4 wheel low-actuator engages front drive shaft but not front diff. 4 hi- no shaft engagement. replaced vac switch, checked vac actuator-good, replaced vac lines that were needed. Green light on switch stays on unless pushing 4-lo. Any suggestions ?? Don't have a lot of money to throw at it.

 

Electric or manual shift transfer case?

Raise only the right front wheel off the ground, engine at idle, trans in park or neutral, select 4WD.
1. Can you rotate the right front wheel by hand?
2. Does it make any clicking noises if/as it rotates?
3. Does the right front axle vacuum actuator, near or under the battery, have manifold vacuum to it?
4. Select 2WD, does vacuum immediately drop to zero at the actuator?

 

electric tc
1. yes
2. no
3. no
4. none there to begin with.
Got a code 2 out of tccm, going to check connections next. Green 4 hi light always on while in 2 wheel hi, engages 4 lo when button pushed. front drive shaft turns but front axle still open. Thanks !!

 

With the engine at idle, transmission in park or neutral, select 2WD: check for manifold vacuum on one of the three lines at the vacuum switch. Located on the driver side of transfer case, inboard and slightly above the front output shaft:



Check the integrity of the 2 remaining vacuum lines:




Edit: During electronic shifting, (mode shift & range shift) the TCCM checks the encoder motor operation. If the encoder motor does not function properly, the TCCM stores an encoder motor DTC 2. Usually this means there's a problem with the encoder motor or its associated wiring.... bad motor, short or open circuit to the encoder motor, poor connection, etc etc. If the encoder motor is not shifting the transfer case, the vacuum switch will not be able to direct vacuum to the actuator under the battery. If the transfer case is not shifting, and constantly in 2WD, you'll never see vacuum at the actuator, and the right front axle will not lock in.