1996 K 1500 with manuel four wheel floor shift will work in four low but will not work in four high (what could be the problem). Dan

Turn on the vehicle.
Hold the brake petal down.
Shift into neutral.
Pull the 4WD lever and shift into 2WD High.

Try shifting the shift selector into Neutral first then try engaging 4wd low. If that doesn't work try shifting into 1st gear and then try engaging 4wd low. The information is inside your owners manual but if this doesn't work please let me know. Also is the light on for which mode your truck is in (2wd or 4wd high)? If not, you may want to check for a blown fuse.

Which of these does your vehicle have ?

Transfer Case - NVG 233-NP1 (Two Speed Selectable)
Transfer Case - NVG 136-NP4(One Speed Automatic)

The New Venture Gear NV233 is an electronic shift transfer, with the following three modes of operation, Two-wheel drive high range, Four-wheel drive high range, Four-wheel drive low range. The gear reduction for low range is provided by a planetary gear set. The floor-mounted shifter has been eliminated. A switch, located on the upper right side of the instrument panel, is used to select the operating range. The indicator lamps on the switch show the current mode of operation. When the four-wheel drive has been selected, the four-wheel drive indicator lamp on the switch is designed to turn on when the front axle has engaged.


Automatic Transfer Case
The single speed automatic transfer case system shifts automatically from rear wheel drive to four wheel drive when the transfer case shift control module (TCSCM) senses the difference in rotation speed of the front propeller shaft and the rear propeller shaft . Two vehicle speed sensors, one located at the rear output shaft area of the transfer case, and the other, located at the front output shaft area of the transfer case, send front and rear propeller shaft rotation speed information to the TCSCM.
When the front and rear output shaft rotations remain the same, the TCSCM sends pulse width modulation signals to the encoder/motor to keep the transfer case in rear wheel drive. When the front and rear output shafts rotations are different, the shift control module sends pulse width modulation signals to the encoder/motor to engage the transfer case into four wheel drive.
The system will automatically transfer a percentage of torque to either the front or rear axles as required to stop all wheel slip. When the front and rear output shafts rotations return to the same speed rotation, the shift control module sends pulse width modulation signals to the encoder/motor to position the transfer case back into rear wheel drive.
When the transfer case is engaged into four wheel drive, a lamp indicator on the instrument cluster will light. The automatic transfer case system is completely automated, no transfer case control button switching system is required.

Do you know what diagnostic trouble code's are ?

DTC C0300 Rear Speed Sensor Malfunction
DTC C0305 Front Speed Sensor Malfunction
DTC C0308 Motor A/B Circuit Low
DTC C0309 Motor A/B Circuit High
DTC C0310 Motor A/B Circuit Open
DTC C0315 Motor Ground Circuit Open
DTC C0374 General System Malfunction
DTC C0376 Front/Rear Shaft Speed Mismatch
DTC C0550 ECU Malfunction
DTC C0611 VIN Information Error
DTC C0895 Device Voltage Malfunction

Not OBD2 engine code's .

On the transfer case
Transfer Case - Electronic Shift
The four-wheel drive electronic shift-on-the-fly feature electrically shifts the vehicle transfer case between 2WD, 4WD HIGH, and 4WD LOW. The system mode is selected by the operator through the mode select switch (MSS) on the instrument panel. The operator is informed which mode the system is in by two instrument cluster indicators: one for 4WD HIGH which appears as 4WD, and one for 4WD LOW, which appears as 4WD LOW. Shifts into 4WD HIGH can be made at any speed. When shifting into 4WD HIGH with the vehicle stationary, tooth blockage may occur preventing shift completion. When the vehicle is driven above 8 km/h (5 mph) the shift will complete. When shifting in or out of 4WD LOW, the four-wheel drive (4WD) control module requires that the vehicle speed be less than 5 km/h (3 mph), the brake pedal be applied, and the transmission be in NEUTRAL (automatic transmission) or the clutch pedal be depressed (manual transmission).
The gearmotor encoder assembly is mounted externally on the transfer case. It drives a rotary cam which moves the mode fork and range fork within the transfer case between the 4WD HIGH, 4WD LOW, and 2WD range positions.
The four-wheel drive (4WD) control module controls the gearmotor encoder assembly that shifts between 4WD HIGH, 4WD LOW, and 2WD modes.

did you turn the locks on the wheels, or check the fuses

Easy 4WD fix, Transfer case linkage adjustment and install ...

? 2:27
https://www.youtube.com/watch?v=Apm1QtTQO8o
Sep 4, 2012 - Uploaded by JerryRigEverything
The Four Wheel Drive isn't always just 'broken' or not working or grinding for some reason. ... Mine won't shift into 4 low only 4 high I think its linkage or angle after doing 4"lift ... Would this fix work for a 2003 jeep grand Cherokee Laredo? ... I have the same problem but on a dodge 4x4 ram 1500 how do I ...

push button type floor shift type high range2wd does transfercase motor make noise did you burn transfercase clutches out? front not engaging but low range for rear help us help u

Do you have it in neutral? Transmission has to be in neutral to shift into and out of 4 low.

Your blazer is equipped with a shift on the fly four wheel drive. That means that at speeds less than fifteen miles per hour you can shift into or out of four wheel drive by simply pushing the four wheel high button. If you wish to shift into four wheel low. Stop, put the transmission into park or neutral, and push the four wheel low button. Same procedure for shifting back out. Never shift into or out of four wheel low while moving. And be careful in four wheel low. At full throttle your still barely moving, you don't want to blow your engine up!

If the Amigo is like other fwd setups,you should be able to pull the floor shifter back one notch for fwd in the standard(or high)driving range.I don't know if you can shift "on the fly" with the Amigo,so I would shift it to 4x4 while stopped in nuetral. When you pull the shifter to the left(towards the driver)and all the way back,that should be 4x4 in the low range(for speeds under 20 mph only). I would not recomend that you drive you vehicle on the highway in low range....The button on the dash may actually be a light to let you know when you are using the fwd. Make sure you kick it back to 2wd when you return on dry pavement.Any Isuzu dealers' service department can also help you on the matter. Good Luck!